Conductive polymer dispersion for improved reliability

ABSTRACT

A dispersion comprising first particles comprising conductive polymer and polyanion and second particles comprising the conductive polymer and said polyanion wherein the first particles have an average particle diameter of at least 1 micron to no more than 10 microns and the second particles have an average particle diameter of at least 1 nm to no more than 600 nm.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention is a divisional application of pending U.S. patentapplication Ser. No. 16/435,762 filed Jun. 10, 2019 which is, in turn, acontinuation-in-part of U.S. patent application Ser. No. 16/165,649filed Oct. 19, 2018 now U.S. Pat. No. 10,650,980 issued May 12, 2020which, in turn, is a divisional application of U.S. patent applicationSer. No. 15/787,126 filed Oct. 18, 2017 now U.S. Pat. No. 10,658,121issued May 19, 2020 all of which are incorporated herein by reference.

BACKGROUND

The present invention is related to improved solid electrolyticcapacitors comprising conductive polymeric cathodes. More specifically,the present invention is related to improvements in the conductivepolymer wherein the improved polymer composition provides improvedcoverage, particularly on edges and corners, thereby providing acapacitor with improved ESR and improved leakage stability in humidenvironments.

Solid electrolytic capacitors are widely used throughout the electronicsindustry. In high voltage applications capacitors with a solidelectrolyte, formed by conductive polymer dispersions, give excellenthigh voltage performance compared to conductive polymer cathodes formedin-situ. These conductive polymer dispersions are prepared by a numberof process steps including polymerization, purification, filtration,homogenization, evaporation, etc. Descriptions of these processes areprovided in U.S. Pat. Nos. 5,300,575; 7,990,684; 7,270,871; 6,000,840and 9,030,806; U.S. Patent Publication No. 2011/0049433 and PCTPublication WO 2010/089111 each of which is incorporated herein byreference.

Capacitors and methods of making capacitors are provided in U.S. Pat.Nos. 7,990,683; 7,754,276 and 7,563,290 each of which is incorporatedherein by reference.

Solid electrolytic capacitors comprising conducting polymer, as thecathode, have several disadvantages. One disadvantage is the difficultyassociated with covering edges and corners of the dielectric. Poorcoverage of conducting polymers on corners and edges of anodized anodesresults in high DC leakage current and causes reliability problems inhumid atmosphere.

Equivalent Series Resistance (ESR) stability of the capacitors requiresthat the interface between the cathode layer, cathodic conductivelayers, conductive adhesive, and leadframe have good mechanicalintegrity during thermo mechanical stresses. Solid electrolyticcapacitors are subject to various thermomechanical stresses duringassembly, molding, board mount reflow etc. During board mount thecapacitors are subjected to temperatures above 250° C. These elevatedtemperatures create stresses in the interfaces due to coefficient ofthermal expansion (CTE) mismatches between the interfaces. The resultantstress causes mechanical weakening of the interfaces. In some cases thismechanical weakening causes delamination. Any physical separationbetween the interfaces causes increases in electrical resistance betweenthe interfaces and thus an increased ESR in the finished capacitor. Thisinterfacial weakness also results in higher ESR shift during highhumidity environment.

European Patent Application EP-A-1746613 improves the process of formingsolid electrolytic capacitor from EP-A-1524678 by virtue of solidparticles having a diameter in the range from 0.7 to 20 μm being addedto the dispersion. The solid particles are particles of electricallyconductive polymer or fillers such as carbonates, silicates, silica,calcium sulphate, barium sulphate, aluminium hydroxide, glass fibres,glass bulbs, wood flour, cellulose powder, carbon black, silicon oxidesor silicon dioxide. The patent claims improved edge and corner coverageby addition of the aforementioned particles in conductive polymerpolyanion dispersion. However, the solid particles of conductive polymerdoes not contain polyanion which makes it non-disperive or insoluble inwater. Thus, the addition of solid particles of conducting polymer inconducting polymer:polyanion dispersion can affect dispersion stability,causes the dispersion to have a very high viscosity, settlements ofsolid particles in the dispersion, and results in poor reproducibilityin performance. Moreover, as mentioned in US Patent Pub. No.2015/0140203 A1, the solid particles makes the polymeric outer filmbrittle, which can cause the outer layer to flake off locally resultingin an increase in the residual current and in the ESR.

To improve coverage without affecting polymeric outer layer filmstrength, WO2010089111A1, which is incorporated herein by reference,reported the use of a group of chemical compounds, referred to ascrosslinkers or primers, which are mostly multi-cationic salts oramines. The crosslinker is applied to the anodized anode prior to theapplication of polymer slurry to achieve good polymer coverage oncorners and edges of the anodized anode. The use of crosslinkereliminated the need of solid particles in conducting polymer dispersionfor coverage improvement. The effectiveness of the crosslinker isattributed to the cross-linking ability of multi-cationic salts oramines to the slurry/dispersion particles. While crosslinkers areadvantageous for improving the coating coverage on corners and edges ofthe anodized anode, the addition of these crosslinkers, which are mostlyionic in nature, has the unintended consequences of degrading theperformance under humidity such as high ESR shift and increased DCleakage in a finished product.

There was been an ongoing need for an improved conductive polymercapable of achieving better corner and edge coverage in a solidelectrolytic capacitor, and process for forming the capacitor, withoutdegrading the ESR and leakage reliability performance in humidconditions.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improvedconductive polymer capable of providing better corner and edge coveragein capacitor.

It is another object of the present invention to provide an improvedcapacitor with improved properties, particularly for use in humidcondition.

These and other advantages are realized in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode; and

forming a conductive polymer layer on the anodized anode wherein theconductive polymer layer comprises first particles comprising conductivepolymer and polyanion and second particles comprising the conductivepolymer and the polyanion wherein the first particles have an averageparticle diameter of at least 1 micron to no more than 10 microns andthe second particles have an average particle diameter of at least 1 nmto no more than 600 nm.

Another embodiment is provided by a solid electrolyte capacitorcomprising: an anodized anode and a conductive polymer layer on theanodized anode wherein the conductive polymer layer comprises firstparticles comprising conductive polymer and polyanion and secondparticles comprising the conductive polymer and polyanion wherein thefirst particles have an average particle diameter of at least 1 micronto no more than 10 microns and the second particles have an averageparticle diameter of at least 1 nm to no more than 600 nm.

Yet another embodiment is provided by a process for forming a dispersioncomprising:

providing a monomer and a polyanion in a solution comprising at least 3wt % to no more than 10 wt % solids of monomer and polyanion; and

polymerization the monomer by high shear polymerization wherein thedispersion comprises first particles comprising conductive polymer andpolyanion and second particles comprising the conductive polymer andpolyanion wherein the first particles have an average particle diameterof at least 1 micron to no more than 10 microns and the second particleshave an average particle diameter of at least 1 nm to no more than 600nm.

Yet another embodiment is provided in a dispersion comprising:

first particles comprising conductive polymer and polyanion wherein thefirst particles have an average particle diameter of at least 1 micronto no more than 10 microns; second particles comprising conductivepolymer and polyanion wherein the second particles have an averageparticle diameter of at least 1 nm to no more than 600 nm; wherein theconductive polymer comprises conjugated groups having the structure ofFormula I:

wherein:R¹ and R² independently represent linear or branched C₁-C₁₆ alkyl orC₂-C₁₈ alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzyl which areunsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, halogen orOR³; or R¹ and R², taken together, are linear C₁-C₆ alkylene which isunsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, halogen,C₃-C₈ cycloalkyl, phenyl, benzyl, C₁-C₄ alkylphenyl, C₁-C₄ alkoxyphenyl,halophenyl, C₁-C₄ alkylbenzyl, C₁-C₄ alkoxybenzyl or halobenzyl, 5-, 6-,or 7-membered heterocyclic structure containing two oxygen elements;R³ represents hydrogen, linear or branched C₁-C₁₆ alkyl or C₂-C₁₈alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzyl which areunsubstituted or substituted by C₁-C₆ alkyl; andX is S, N or O; andthe polyanion is represented by Formula 2:A_(x)B_(y)C_(z)   Formula 2wherein:A is polystyrenesulfonic acid or salt of polystyrenesulfonate;B and C separately represent polymerized units substituted with a groupselected from:-carboxyl groups;—C(O)OR⁶ wherein R⁶ is selected from the group consisting of:an alkyl of 1 to 20 carbons optionally substituted with a functionalgroup selected from the group consisting of hydroxyl, carboxyl, amine,epoxy, silane, amide, imide, thiol, alkene, alkyne, azide, phosphate,acrylate, anhydride and—(CHR⁷CH₂O)_(b)—R⁸ wherein:R⁷ is selected from a hydrogen or an alkyl of 1 to 7 carbons;b is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR⁷CH₂O— group; andR⁸ is selected from the group consisting of hydrogen, silane, phosphate,acrylate, an alkyl of 1 to 9 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate, and anhydride;—C(O)—NHR⁹ wherein:R⁹ is hydrogen or an alkyl of 1 to 20 carbons optionally substitutedwith a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride;—C₆H₄—R¹⁹ wherein:R¹⁹ is selected from:a hydrogen or alkyl optionally substituted with a functional groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, phosphate, azide, acrylateand anhydride;a reactive group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, imide, amide, thiol, alkene, alkyne,phosphate, azide, acrylate, anhydride and —(O(CHR¹¹CH₂O)_(d)—R¹²wherein:R¹¹ is a hydrogen or an alkyl of 1 to 7 carbons;d is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹¹CH₂O— group;R¹² is selected from the group consisting of hydrogen, an alkyl of 1 to9 carbons optionally substituted with a functional group selected fromthe group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, phosphate, azide, acrylate and anhydride;—C₆H₄—O—R¹³ wherein:R¹³ is selected from:a hydrogen or an alkyl optionally substituted with a reactive groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphateand anhydride;a reactive group selected from the group consisting of epoxy, silane,alkene, alkyne, acrylate, phosphate and—(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons;e is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹⁴CH₂O— group; andR¹⁵ is selected from the group consisting of hydrogen and an alkyl of 1to 9 carbons optionally substituted with a functional group selectedfrom the group consisting of hydroxyl, carboxyl, amine, epoxy, silane,amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphate andanhydride;x, y and z, taken together are sufficient to form a polyanion with amolecular weight of at least 100 to no more than 500,000;y/x is 0 to 100; andz is 0 to a ratio z/x of no more than 100.

Yet another embodiment is provided in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode; and

forming a conductive polymer layer on the anodized anode wherein theconductive polymer layer comprises first particles comprising conductivepolymer and polyanion and second particles comprising the conductivepolymer and the polyanion wherein the first particles have an averageparticle diameter of at least 1 micron to no more than 10 microns andthe second particles have an average particle diameter of at least 1 nmto no more than 600 nm wherein the conductive polymer layer comprises aninternal polymer layer and an external polymer layer and the internalpolymer comprises pre-polymerized conductive polymer.

Yet another embodiment is provided in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode;

applying a layer comprising an organometallic compound on the anodizedanode; and forming a pre-polymerized conductive polymer layer on theorganometallic compound layer wherein the conductive polymer layercomprises first particles comprising conductive polymer and polyanionand second particles comprising the conductive polymer and the polyanionwherein the first particles have an average particle diameter of atleast 1 micron to no more than 10 microns and the second particles havean average particle diameter of at least 1 nm to no more than 600 nmwherein the conductive polymer layer comprises an internal polymer layerand an external polymer layer.

Yet another embodiment is provided in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode; and

forming a conductive polymer layer on the anodized anode wherein theconductive polymer layer comprises first particles comprising conductivepolymer and polyanion and second particles comprising the conductivepolymer and the polyanion wherein the first particles have an averageparticle diameter of at least 1 micron to no more than 10 microns andthe second particles have an average particle diameter of at least 1 nmto no more than 600 nm wherein the forming of the conductive layercomprises applying a dispersion comprising the first particles and thesecond particles; andwherein a portion of the dispersion is further subjected to rotor-statorhigh shear mixing, ultrasonic mixing, acoustic mixing, high-pressurehomogenizer or a high shearing homogenizer.

Yet another embodiment is provided in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode; and

forming a conductive polymer layer on the anodized anode wherein theconductive polymer layer comprises first particles comprising conductivepolymer and polyanion and second particles comprising the conductivepolymer and the polyanion wherein the first particles have an averageparticle diameter of at least 1 micron to no more than 10 microns andthe second particles have an average particle diameter of at least 1 nmto no more than 600 nm wherein the polyanion is represented by Formula2:A_(x)B_(y)C_(z)   Formula 2wherein:A is polystyrenesulfonic acid or salt of polystyrenesulfonate;B and C separately represent polymerized units substituted with a groupselected from:-carboxyl groups;—C(O)OR⁶ wherein R⁶ is selected from the group consisting of:an alkyl of 1 to 20 carbons optionally substituted with a functionalgroup selected from the group consisting of hydroxyl, carboxyl, amine,epoxy, silane, amide, imide, thiol, alkene, alkyne, azide, phosphate,acrylate, anhydride and—(CHR⁷CH₂O)_(b)—R⁸ wherein:R⁷ is selected from a hydrogen or an alkyl of 1 to 7 carbons;b is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR⁷CH₂O— group; andR⁸ is selected from the group consisting of hydrogen, silane, phosphate,acrylate, an alkyl of 1 to 9 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate, and anhydride;—C(O)—NHR⁹ wherein:R⁹ is hydrogen or an alkyl of 1 to 20 carbons optionally substitutedwith a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride;—C₆H₄—R¹⁹ wherein:R¹⁹ is selected from:a hydrogen or alkyl optionally substituted with a functional groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, phosphate, azide, acrylateand anhydride;a reactive group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, imide, amide, thiol, alkene, alkyne,phosphate, azide, acrylate, anhydride and —(O(CHR¹¹CH₂O)_(d)—R¹²wherein:R¹¹ is a hydrogen or an alkyl of 1 to 7 carbons;d is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹¹CH₂O— group;R¹² is selected from the group consisting of hydrogen, an alkyl of 1 to9 carbons optionally substituted with a functional group selected fromthe group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, phosphate, azide, acrylate and anhydride;—C₆H₄—O—R¹³ wherein:R¹³ is selected from:a hydrogen or an alkyl optionally substituted with a reactive groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphateand anhydride;a reactive group selected from the group consisting of epoxy, silane,alkene, alkyne, acrylate, phosphate and—(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons;e is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹⁴CH₂O— group; andR¹⁵ is selected from the group consisting of hydrogen and an alkyl of 1to 9 carbons optionally substituted with a functional group selectedfrom the group consisting of hydroxyl, carboxyl, amine, epoxy, silane,amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphate andanhydride;x, y and z, taken together are sufficient to form a polyanion with amolecular weight of at least 100 to no more than 500,000;y/x is 0 to 100; andz is 0 to a ratio z/x of no more than 100;wherein the first particles and the second particles are in adispersion;wherein a first part of the dispersion is formed by high shearpolymerization of a monomer solution and a second part of the dispersionis further subjected to rotor-stator high shear mixing, ultrasonicmixing, acoustic mixing, high-pressure homogenizer or a high shearinghomogenizer.

Yet another embodiment is provided in a solid electrolyte capacitorcomprising:

an anodized anode; and

a conductive polymer layer on the anodized anode wherein the conductivepolymer layer comprises an internal polymer layer and an externalpolymer layer and further comprises first particles comprisingconductive polymer and polyanion and second particles comprising theconductive polymer and the polyanion wherein the first particles have anaverage particle diameter of at least 1 micron to no more than 10microns and the second particles have an average particle diameter of atleast 1 nm to no more than 600 nm;wherein the polyanion is represented by Formula 2:A_(x)B_(y)C_(z)   Formula 2wherein:A is polystyrenesulfonic acid or salt of polystyrenesulfonate;B and C separately represent polymerized units substituted with a groupselected from:-carboxyl groups;—C(O)OR⁶ wherein R⁶ is selected from the group consisting of:an alkyl of 1 to 20 carbons optionally substituted with a functionalgroup selected from the group consisting of hydroxyl, carboxyl, amine,epoxy, silane, amide, imide, thiol, alkene, alkyne, azide, phosphate,acrylate, anhydride and—(CHR⁷CH₂O)_(b)—R⁸ wherein:R⁷ is selected from a hydrogen or an alkyl of 1 to 7 carbons;b is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR⁷CH₂O— group; andR⁸ is selected from the group consisting of hydrogen, silane, phosphate,acrylate, an alkyl of 1 to 9 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate, and anhydride;—C(O)—NHR⁹ wherein:R⁹ is hydrogen or an alkyl of 1 to 20 carbons optionally substitutedwith a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride;—C₆H₄—R¹⁹ wherein:R¹⁹ is selected from:a hydrogen or alkyl optionally substituted with a functional groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, phosphate, azide, acrylateand anhydride;a reactive group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, imide, amide, thiol, alkene, alkyne,phosphate, azide, acrylate, anhydride and —(O(CHR¹¹CH₂O)_(d)—R¹²wherein:R¹¹ is a hydrogen or an alkyl of 1 to 7 carbons;d is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹¹CH₂O— group;R¹² is selected from the group consisting of hydrogen, an alkyl of 1 to9 carbons optionally substituted with a functional group selected fromthe group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, phosphate, azide, acrylate and anhydride;—C₆H₄—O—R¹³ wherein:R¹³ is selected from:a hydrogen or an alkyl optionally substituted with a reactive groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphateand anhydride;a reactive group selected from the group consisting of epoxy, silane,alkene, alkyne, acrylate, phosphate and—(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons;e is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹⁴CH₂O— group; andR¹⁵ is selected from the group consisting of hydrogen and an alkyl of 1to 9 carbons optionally substituted with a functional group selectedfrom the group consisting of hydroxyl, carboxyl, amine, epoxy, silane,amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphate andanhydride;x, y and z, taken together are sufficient to form a polyanion with amolecular weight of at least 100 to no more than 500,000;y/x is 0 to 100; andz is 0 to a ratio z/x of no more than 100 wherein:y represents 10 to 30% and z represents 0 to 20% of the sum total ofx+y+z; and wherein the external polymer layer comprises the polyanion.

Yet another embodiment is provided in a dispersion comprising:

first particles comprising conductive polymer and polyanion wherein thefirst particles have an average particle diameter of at least 1 micronto no more than 10 microns; second particles comprising the conductivepolymer and the polyanion wherein the second particles have an averageparticle diameter of at least 1 nm to no more than 600 nm;wherein the conductive polymer comprises conjugated groups having thestructure of Formula I:

wherein:R¹ and R² independently represent linear or branched C₁-C₁₆ alkyl orC₂-C₁₈ alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzyl which areunsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, halogen orOR³; or R¹ and R², taken together, are linear C₁-C₆ alkylene which isunsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, halogen,C₃-C₈ cycloalkyl, phenyl, benzyl, C₁-C₄ alkylphenyl, C₁-C₄ alkoxyphenyl,halophenyl, C₁-C₄ alkylbenzyl, C₁-C₄ alkoxybenzyl or halobenzyl, 5-, 6-,or 7-membered heterocyclic structure containing two oxygen elements;R³ represents hydrogen, linear or branched C₁-C₁₆ alkyl or C₂-C₁₈alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzyl which areunsubstituted or substituted by C₁-C₆ alkyl; andX is S, N or O; andthe polyanion is represented by Formula 2:A_(x)B_(y)C_(z)   Formula 2wherein:A is polystyrenesulfonic acid or salt of polystyrenesulfonate;B and C separately represent polymerized units substituted with a groupselected from:-carboxyl groups;—C(O)OR⁶ wherein R⁶ is selected from the group consisting of:an alkyl of 1 to 20 carbons optionally substituted with a functionalgroup selected from the group consisting of hydroxyl, carboxyl, amine,epoxy, silane, amide, imide, thiol, alkene, alkyne, azide, phosphate,acrylate, anhydride and—(CHR⁷CH₂O)_(b)—R⁸ wherein:R⁷ is selected from a hydrogen or an alkyl of 1 to 7 carbons;b is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR⁷CH₂O— group; andR⁸ is selected from the group consisting of hydrogen, silane, phosphate,acrylate, an alkyl of 1 to 9 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate, and anhydride;—C(O)—NHR⁹ wherein:R⁹ is hydrogen or an alkyl of 1 to 20 carbons optionally substitutedwith a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride;—C₆H₄—R¹⁹ wherein:R¹⁹ is selected from:a hydrogen or alkyl optionally substituted with a functional groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, phosphate, azide, acrylateand anhydride;a reactive group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, imide, amide, thiol, alkene, alkyne,phosphate, azide, acrylate, anhydride and —(O(CHR¹¹CH₂O)_(d)—R¹²wherein:R¹¹ is a hydrogen or an alkyl of 1 to 7 carbons;d is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹¹CH₂O— group;R¹² is selected from the group consisting of hydrogen, an alkyl of 1 to9 carbons optionally substituted with a functional group selected fromthe group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, phosphate, azide, acrylate and anhydride;—C₆H₄—O—R¹³ wherein:R¹³ is selected from:a hydrogen or an alkyl optionally substituted with a reactive groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphateand anhydride;a reactive group selected from the group consisting of epoxy, silane,alkene, alkyne, acrylate, phosphate and—(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons;e is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹⁴CH₂O— group; andR¹⁵ is selected from the group consisting of hydrogen and an alkyl of 1to 9 carbons optionally substituted with a functional group selectedfrom the group consisting of hydroxyl, carboxyl, amine, epoxy, silane,amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphate andanhydride;x, y and z, taken together are sufficient to form a polyanion with amolecular weight of at least 100 to no more than 500,000;y/x is 0 to 100; andz is 0 to a ratio z/x of no more than 100 wherein a portion of thedispersion is further subjected to rotor-stator high shear mixing,ultrasonic mixing, acoustic mixing, high-pressure homogenizing or highshearing homogenizing.

Yet another embodiment is provided in a process for forming anelectrolytic capacitor comprising: providing an anode comprising adielectric coated with an organometallic compound and forming a firstconductive polymer layer comprises a polyanion and a conductive polymer,applying a second polymer slurry comprises a second conductive polymerand polyanion where in the polyanion is PSS copolymer.

Yet another embodiment is provided in a process for forming anelectrolytic capacitor comprising: providing an anode comprising adielectric coated with an organometallic compound and forming a firstconductive polymer layer wherein the first conductive polymer layercomprises a polyanion and a conductive polymer, applying a secondpolymer slurry comprises a polyanion where in the second slurrycomprises multimodal particles of PEDOT:Polyanion.

Yet another embodiment is provided in a process for forming anelectrolytic capacitor comprising: providing an anode comprising adielectric coated with an organometallic compound and forming a firstconductive polymer layer the first conductive polymer layer comprises apolyanion and a conductive polymer, applying a second polymer slurrycomprises a polyanion where in the second slurry comprises at leastbimodal particle sizes of PEDOT:Polyanion where in the polyanion is PSScopolymer.

Yet another embodiment is provided in a process for forming anelectrolytic capacitor comprising: providing an anode comprising adielectric coated with an organometallic compound and forming a firstconductive polymer layer is a prepolymerized polymer, applying a secondpolymer slurry comprises a second conductive polymer and polyanion wherein the polyanion is PSS copolymer.

Yet another embodiment is provided in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode; and

forming a conductive polymer layer on the anodized anode wherein theconductive polymer layer comprises first particles comprising conductivepolymer and polyanion and second particles comprising the conductivepolymer and the polyanion wherein the first particles have an averageparticle diameter of at least 1 micron to no more than 10 microns andthe second particles have an average particle diameter of at least 1 nmto no more than 600 nm wherein the conductive polymer layer comprises aninternal polymer layer and an external polymer layer and the internalpolymer comprises pre-polymerized conductive polymer.

Yet another embodiment is provided in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode;

applying a layer comprising an organometallic compound on the anodizedanode; and forming a pre-polymerized conductive polymer layer on theorganometallic compound layer wherein the conductive polymer layercomprises first particles comprising conductive polymer and polyanionand second particles comprising the conductive polymer and the polyanionwherein the first particles have an average particle diameter of atleast 1 micron to no more than 10 microns and the second particles havean average particle diameter of at least 1 nm to no more than 600 nmwherein the conductive polymer layer comprises an internal polymer layerand an external polymer layer.

Yet another embodiment is provided in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode; and

forming a conductive polymer layer on the anodized anode wherein theconductive polymer layer comprises first particles comprising conductivepolymer and polyanion and second particles comprising the conductivepolymer and the polyanion wherein the first particles have an averageparticle diameter of at least 1 micron to no more than 10 microns andthe second particles have an average particle diameter of at least 1 nmto no more than 600 nm wherein the forming of the conductive layercomprises applying a dispersion comprising the first particles and thesecond particles; and wherein a portion of the dispersion is furthersubjected to rotor-stator high shear mixing, ultrasonic mixing, acousticmixing, high-pressure homogenizer or a high shearing homogenizer.

Yet another embodiment is provided in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode; and

forming a conductive polymer layer on the anodized anode wherein theconductive polymer layer comprises first particles comprising conductivepolymer and polyanion and second particles comprising the conductivepolymer and the polyanion wherein the first particles have an averageparticle diameter of at least 1 micron to no more than 10 microns andthe second particles have an average particle diameter of at least 1 nmto no more than 600 nm wherein the polyanion is represented by Formula2:A_(x)B_(y)C_(z)   Formula 2wherein:A is polystyrenesulfonic acid or salt of polystyrenesulfonate;B and C separately represent polymerized units substituted with a groupselected from:-carboxyl groups;—C(O)OR⁶ wherein R⁶ is selected from the group consisting of:an alkyl of 1 to 20 carbons optionally substituted with a functionalgroup selected from the group consisting of hydroxyl, carboxyl, amine,epoxy, silane, amide, imide, thiol, alkene, alkyne, azide, phosphate,acrylate, anhydride and—(CHR⁷CH₂O)_(b)—R⁸ wherein:R⁷ is selected from a hydrogen or an alkyl of 1 to 7 carbons;b is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR⁷CH₂O— group; andR⁸ is selected from the group consisting of hydrogen, silane, phosphate,acrylate, an alkyl of 1 to 9 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate, and anhydride;—C(O)—NHR⁹ wherein:R⁹ is hydrogen or an alkyl of 1 to 20 carbons optionally substitutedwith a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride;—C₆H₄—R¹⁹ wherein:R¹⁹ is selected from:a hydrogen or alkyl optionally substituted with a functional groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, phosphate, azide, acrylateand anhydride;a reactive group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, imide, amide, thiol, alkene, alkyne,phosphate, azide, acrylate, anhydride and —(O(CHR¹¹CH₂O)_(d)—R¹²wherein:R¹¹ is a hydrogen or an alkyl of 1 to 7 carbons;d is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹¹CH₂O— group;R¹² is selected from the group consisting of hydrogen, an alkyl of 1 to9 carbons optionally substituted with a functional group selected fromthe group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, phosphate, azide, acrylate and anhydride;—C₆H₄—O—R¹³ wherein:R¹³ is selected from:a hydrogen or an alkyl optionally substituted with a reactive groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphateand anhydride;a reactive group selected from the group consisting of epoxy, silane,alkene, alkyne, acrylate, phosphate and—(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons;e is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹⁴CH₂O— group; andR¹⁵ is selected from the group consisting of hydrogen and an alkyl of 1to 9 carbons optionally substituted with a functional group selectedfrom the group consisting of hydroxyl, carboxyl, amine, epoxy, silane,amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphate andanhydride;x, y and z, taken together are sufficient to form a polyanion with amolecular weight of at least 100 to no more than 500,000;y/x is 0 to 100; andz is 0 to a ratio z/x of no more than 100;wherein the first particles and second particles are in a dispersion;wherein a first part of the dispersion is formed by high shearpolymerization of a monomer solution and a second part of the dispersionis further subjected to rotor-stator high shear mixing, ultrasonicmixing, acoustic mixing, high-pressure homogenizer or a high shearinghomogenizer.

Yet another embodiment is provided in a process for forming a solidelectrolyte capacitor comprising:

providing an anodized anode; and

forming a conductive polymer layer on said anodized anode wherein saidconductive polymer layer comprises an internal polymer layer and anexternal polymer layer and further comprises first particles comprisingconductive polymer and polyanion and second particles comprising saidconductive polymer and said polyanion wherein said first particles havean average particle diameter of at least 1 micron to no more than 10microns and said second particles have an average particle diameter ofat least 1 nm to no more than 600 nm;wherein said polyanion is represented by Formula 2:A_(x)B_(y)C_(z)   Formula 2wherein:A is polystyrenesulfonic acid or salt of polystyrenesulfonate;B and C separately represent polymerized units substituted with a groupselected from:-carboxyl groups;—C(O)OR⁶ wherein R⁶ is selected from the group consisting of:an alkyl of 1 to 20 carbons optionally substituted with a functionalgroup selected from the group consisting of hydroxyl, carboxyl, amine,epoxy, silane, amide, imide, thiol, alkene, alkyne, azide, phosphate,acrylate, anhydride and—(CHR⁷CH₂O)_(b)—R⁸ wherein:R⁷ is selected from a hydrogen or an alkyl of 1 to 7 carbons;b is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR⁷CH₂O— group; andR⁸ is selected from the group consisting of hydrogen, silane, phosphate,acrylate, an alkyl of 1 to 9 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate, and anhydride;—C(O)—NHR⁹ wherein:R⁹ is hydrogen or an alkyl of 1 to 20 carbons optionally substitutedwith a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride;—C₆H₄—R¹⁹ wherein:R¹⁹ is selected from:a hydrogen or alkyl optionally substituted with a functional groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, phosphate, azide, acrylateand anhydride;a reactive group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, imide, amide, thiol, alkene, alkyne,phosphate, azide, acrylate, anhydride and —(O(CHR¹¹CH₂O)_(d)—R¹²wherein:R¹¹ is a hydrogen or an alkyl of 1 to 7 carbons;d is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹¹CH₂O— group;R¹² is selected from the group consisting of hydrogen, an alkyl of 1 to9 carbons optionally substituted with a functional group selected fromthe group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, phosphate, azide, acrylate and anhydride;—C₆H₄—O—R¹³ wherein:R¹³ is selected from:a hydrogen or an alkyl optionally substituted with a reactive groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphateand anhydride;a reactive group selected from the group consisting of epoxy, silane,alkene, alkyne, acrylate, phosphate and—(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons;e is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹⁴CH₂O— group; andR¹⁵ is selected from the group consisting of hydrogen and an alkyl of 1to 9 carbons optionally substituted with a functional group selectedfrom the group consisting of hydroxyl, carboxyl, amine, epoxy, silane,amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphate andanhydride;x, y and z, taken together are sufficient to form a polyanion with amolecular weight of at least 100 to no more than 500,000;y/x is 0 to 100; andz is 0 to a ratio z/x of no more than 100 wherein:y represents 10 to 30% and z represents 0 to 20% of the sum total ofx+y+z; and wherein the external polymer layer comprises the polyanion.

Yet another embodiment is provided in a capacitor comprising:

an anodized anode; and a conductive polymer layer on the anodized anodewherein the conductive polymer layer comprises first particlescomprising conductive polymer and polyanion and second particlescomprising the conductive polymer and the polyanion wherein the firstparticles have an average particle diameter of at least 1 micron to nomore than 10 microns and the second particles have an average particlediameter of at least 1 nm to no more than 600 nm wherein the conductivepolymer layer comprises an internal polymer layer and an externalpolymer layer and the internal polymer comprises pre-polymerizedconductive polymer.

Yet another embodiment is provided in a capacitor comprising:

an anodized anode;

a layer comprising an organometallic compound on the anodized anode; anda conductive polymer layer on the organometallic compound layer whereinthe conductive polymer layer comprises first particles comprisingconductive polymer and polyanion and second particles comprising theconductive polymer and the polyanion wherein the first particles have anaverage particle diameter of at least 1 micron to no more than 10microns and the second particles have an average particle diameter of atleast 1 nm to no more than 600 nm wherein the conductive polymer layercomprises an internal polymer layer and an external polymer layer.

Yet another embodiment is provided in a capacitor comprising:

an anodized anode; and

a conductive polymer layer on the anodized anode wherein the conductivepolymer layer comprises an internal polymer layer and an externalpolymer layer and further comprises first particles comprisingconductive polymer and polyanion and second particles comprising theconductive polymer and the polyanion wherein the first particles have anaverage particle diameter of at least 1 micron to no more than 10microns and the second particles have an average particle diameter of atleast 1 nm to no more than 600 nm;wherein the polyanion is represented by Formula 2:A_(x)B_(y)C_(z)   Formula 2wherein:A is polystyrenesulfonic acid or salt of polystyrenesulfonate;B and C separately represent polymerized units substituted with a groupselected from:-carboxyl groups;—C(O)OR⁶ wherein R⁶ is selected from the group consisting of:an alkyl of 1 to 20 carbons optionally substituted with a functionalgroup selected from the group consisting of hydroxyl, carboxyl, amine,epoxy, silane, amide, imide, thiol, alkene, alkyne, azide, phosphate,acrylate, anhydride and—(CHR⁷CH₂O)_(b)—R⁸ wherein:R⁷ is selected from a hydrogen or an alkyl of 1 to 7 carbons;b is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR⁷CH₂O— group; andR⁸ is selected from the group consisting of hydrogen, silane, phosphate,acrylate, an alkyl of 1 to 9 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate, and anhydride;—C(O)—NHR⁹ wherein:R⁹ is hydrogen or an alkyl of 1 to 20 carbons optionally substitutedwith a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride;—C₆H₄—R¹⁹ wherein:R¹⁹ is selected from:a hydrogen or alkyl optionally substituted with a functional groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, phosphate, azide, acrylateand anhydride;a reactive group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, imide, amide, thiol, alkene, alkyne,phosphate, azide, acrylate, anhydride and —(O(CHR¹¹CH₂O)_(d)—R¹²wherein:R¹¹ is a hydrogen or an alkyl of 1 to 7 carbons;d is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹¹CH₂O— group;R¹² is selected from the group consisting of hydrogen, an alkyl of 1 to9 carbons optionally substituted with a functional group selected fromthe group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, phosphate, azide, acrylate and anhydride;—C₆H₄—O—R¹³ wherein:R¹³ is selected from:a hydrogen or an alkyl optionally substituted with a reactive groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphateand anhydride;a reactive group selected from the group consisting of epoxy, silane,alkene, alkyne, acrylate, phosphate and—(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons;e is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹⁴CH₂O— group; andR¹⁵ is selected from the group consisting of hydrogen and an alkyl of 1to 9 carbons optionally substituted with a functional group selectedfrom the group consisting of hydroxyl, carboxyl, amine, epoxy, silane,amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphate andanhydride;x, y and z, taken together are sufficient to form a polyanion with amolecular weight of at least 100 to no more than 500,000;y/x is 0 to 100; andz is 0 to a ratio z/x of no more than 100 wherein:y represents 10 to 30% and z represents 0 to 20% of the sum total ofx+y+z; and wherein the external polymer layer comprises the polyanion.

Yet another embodiment is provided in a dispersion comprising:

first particles comprising conductive polymer and polyanion wherein thefirst particles have an average particle diameter of at least 1 micronto no more than 10 microns; second particles comprising the conductivepolymer and the polyanion wherein the second particles have an averageparticle diameter of at least 1 nm to no more than 600 nm;wherein the conductive polymer comprises conjugated groups having thestructure of Formula I:

wherein:R¹ and R² independently represent linear or branched C₁-C₁₆ alkyl orC₂-C₁₈ alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzyl which areunsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, halogen orOR³; or R¹ and R², taken together, are linear C₁-C₆ alkylene which isunsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, halogen,C₃-C₈ cycloalkyl, phenyl, benzyl, C₁-C₄ alkylphenyl, C₁-C₄ alkoxyphenyl,halophenyl, C₁-C₄ alkylbenzyl, C₁-C₄ alkoxybenzyl or halobenzyl, 5-, 6-,or 7-membered heterocyclic structure containing two oxygen elements;R³ represents hydrogen, linear or branched C₁-C₁₆ alkyl or C₂-C₁₈alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzyl which areunsubstituted or substituted by C₁-C₆ alkyl; andX is S, N or O; andthe polyanion is represented by Formula 2:A_(x)B_(y)C_(z)   Formula 2wherein:A is polystyrenesulfonic acid or salt of polystyrenesulfonate;B and C separately represent polymerized units substituted with a groupselected from:-carboxyl groups;—C(O)OR⁶ wherein R⁶ is selected from the group consisting of:an alkyl of 1 to 20 carbons optionally substituted with a functionalgroup selected from the group consisting of hydroxyl, carboxyl, amine,epoxy, silane, amide, imide, thiol, alkene, alkyne, azide, phosphate,acrylate, anhydride and—(CHR⁷CH₂O)_(b)—R⁸ wherein:R⁷ is selected from a hydrogen or an alkyl of 1 to 7 carbons;b is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR⁷CH₂O— group; andR⁸ is selected from the group consisting of hydrogen, silane, phosphate,acrylate, an alkyl of 1 to 9 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate, and anhydride;—C(O)—NHR⁹ wherein:R⁹ is hydrogen or an alkyl of 1 to 20 carbons optionally substitutedwith a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride;—C₆H₄—R¹⁹ wherein:R¹⁹ is selected from:a hydrogen or alkyl optionally substituted with a functional groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, phosphate, azide, acrylateand anhydride;a reactive group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, imide, amide, thiol, alkene, alkyne,phosphate, azide, acrylate, anhydride and —(O(CHR¹¹CH₂O)_(d)—R¹²wherein:R¹¹ is a hydrogen or an alkyl of 1 to 7 carbons;d is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹¹CH₂O— group;R¹² is selected from the group consisting of hydrogen, an alkyl of 1 to9 carbons optionally substituted with a functional group selected fromthe group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, phosphate, azide, acrylate and anhydride;—C₆H₄—O—R¹³ wherein:R¹³ is selected from:a hydrogen or an alkyl optionally substituted with a reactive groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,silane, amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphateand anhydride;a reactive group selected from the group consisting of epoxy, silane,alkene, alkyne, acrylate, phosphate and—(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons;e is an integer from 1 to the number sufficient to provide a molecularweight of up to 200,000 for the —CHR¹⁴CH₂O— group; andR¹⁵ is selected from the group consisting of hydrogen and an alkyl of 1to 9 carbons optionally substituted with a functional group selectedfrom the group consisting of hydroxyl, carboxyl, amine, epoxy, silane,amide, imide, thiol, alkene, alkyne, azide, acrylate, phosphate andanhydride;x, y and z, taken together are sufficient to form a polyanion with amolecular weight of at least 100 to no more than 500,000;y/x is 0 to 100; andz is 0 to a ratio z/x of no more than 100 wherein a portion of thedispersion is further subjected to rotor-stator high shear mixing,ultrasonic mixing, acoustic mixing, high-pressure homogenizing or highshearing homogenizing.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic cross-sectional view of a solid electrolyticcapacitor.

FIG. 2 is a flow chart representation of an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is related to an improved conductive polymerdispersion for use in solid electrolyte capacitors, an improved solidelectrolyte capacitor comprising the conductive polymer as a cathode, aslurry comprising the conductive polymer, and a method for making theimproved solid electrolyte capacitor. More particularly, the presentinvention is related to an improved polymerization method for conductivepolymer dispersions suitable for use in an improved solid electrolytecapacitor wherein the improvement arises, at least in part, by improvedcorner and edge coverage on the anodized anode and improved interfacialadhesion in cathode layers.

It has been found that, surprisingly, complete corner and edge coverageand improved interfacial adhesion in a solid electrolyte capacitor canbe achieved by applying a mixture comprising a dispersion of conductivepolymer with at least a bimodal size distribution of a conductivepolymer:polyanion complex particles in a solvent. The first particleshave a median particle size (D₅₀) which is at least 1 micron to no morethan 10 microns. More preferably, the first particles have a D₅₀ whichis at least 1 micron to no more than 5 microns and even more preferablyat least 2 microns to no more than 4 microns. The second particles havea D₅₀ of at least 1 nm to no more than 600 nm more preferably at least100 nm to no more than 500 nm and even more preferably at least 200 nmto no more than 400 nm. The term average diameter, reported as D₅₀, isthe mass-median diameter or average particle diameter by mass. Whilebeing described as bi-modal dispersion having more than two distinctparticle sizes are contemplated.

It is preferred that the particles of polymer and anion have at least 5wt % to no more than 95 wt % first particles with a d₅₀ of at least 1micron to no more than 10 microns, more preferably at least 25 wt % tono more than 75 wt % and even more preferably at least 40 wt % to nomore than 60 wt %. It is also preferred that the particles of polymerand anion have at least 5 wt % to no more than 95 wt % second particleswith a d₅₀ of at least 1 nm to no more than 600 nm, more preferably atleast 25 wt % to no more than 75 wt % and even more preferably at least40 wt % to no more than 60 wt %.

It has been found, surprisingly, the ratio adjustment of first particlesand second particles in conducting polymer dispersion through postprocessing a part of dispersion impact polyer film quality. The postprocessing techniques can be high shear mixing, ultrasonic mixing,acoustic mixing, high-pressure homogenizing or high shearinghomogenizing mixing. The at least bimodal size distribution ofconductive polymer:polyanion particles leads to significantly improvedcorner and edge coverage compared to prior art dispersions withmonomodal particle size distribution. The result is a solid electrolyticcapacitor with significantly improved ESR and improved leakagereliability in humid conditions. The present invention provides for asolid electrolytic capacitor with an ESR shift of less than 100% and aleakage of less than 0.1 CV after 1000 hrs load at 85° C. and 85%relative humidity.

In a particularly preferred embodiment the internal polymer layercomprises smaller particles and the external polymer layer comprises anat least bimodal size distribution of conductive polymer:polyanionparticles.

The invention will be described with reference to the figures forming anintegral, non-limiting element of the disclosure.

A capacitor of the invention will be described with reference to FIG. 1wherein a solid electrolytic capacitor is illustrated in cross-sectionalschematic view. In FIG. 1, the solid electrolytic capacitor, 1,comprises an anode, 2, with a dielectric, 3, thereon. After completionthe conductive polymeric layer, 4, is essentially a continuouspreferably un-striated layer, formed by multiple process steps and willtherefore be described herein with each layer discussed separately forthe purposes of illustration and clarity. It is well known thatattaching a lead to a conductive polymer layer is difficult and it istherefore standard in the art to apply an attachment layer, 5, typicallycomprising layers containing conductive carbon on the conductive polymerlayer and silver containing layers on the carbon containing layer. Acathode lead, 7, is attached to the attachment layer by a conductiveadhesive. An anode lead, 6, is attached to a lead wire, 8, typically bywelding and the entire assembly, except for portions of the cathode leadand anode lead, are encapsulated in a non-conductive material, 9, suchas a resin.

The first conductive polymer layer, 4¹, applied is referred to as aninternal polymer layer and is formed in a manner sufficient to allow theinterstitial areas of the porous dielectric to be adequately coated. Thefirst conductive polymer layer typically comprises sublayers which areformed sequentially preferably from common components and under commonconditions suitable to coat the interstitial areas of the porousdielectric. The first conductive polymer layer typically comprises 1 to5 layers with each containing a conjugated conductive polymer.

The first conductive polymer layer can have the same conductive polymerand polyanion as subsequent layers, however, the first conductivepolymer layer is preferably formed by at least one application of aconductive polymer formed by in-situ polymerization formed fromsolutions of monomer(s), oxidant and dopant(s) or by at least oneapplication of a conductive polymer solution or dispersion having smallaverage particle sizes thereby allowing for adequate penetration. In oneembodiment the internal polymer layer is formed from a dispersioncomprising particles of conductive polymer and polyanion wherein theparticle size a D₅₀ of 10 to 50 nm. More preferably the internal polymerhas particle size with a D₅₀ of 10 to 30 nm and more preferably 10-20nm. In one embodiment the internal polymer layer is free of in-situpolymerized conducting polymer.

The internal polymer layer may further coated on adhesion promotinglayer to improve adhesion between dielectric and conducting polymerlayer. The examples of adhesion promoter such as organometalliccompounds or organofunctional silanes or hydrolyzates ororganofunctional silanes containing weak acid, phosphates thereof, e.g.3-glycidoxypropyl-trialkoxysilane, 3-aminopropyltriethoxysilane,3-mercaptopropyltrimethoxysilane,3-methacryloyloxy-propyltrimethoxysilane; vinyltrichlorosilane,vinyl(β-methoxysilane), vinyltriethoxysilane, γ-methacryloxysilane,β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane,N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane,N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane,γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane,γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, or thelike. or water soluble monomers/oligomers/polymers containing reactivegroups such as acid, alcohol, phenol, amines, epoxy, acrylates etc.Example of The weak acid in organofunctional silanes can be acetic acid,phosphoric acid, or the like. The internal polymer layer may furthercomprise small molecular or polymeric counterions including thepolyanion described elsewhere herein. In one embodiment theorganometallic compound is applied to the dielectric, or the surface ofthe anodized anode, and the internal polymer layer is formed thereon. Inanother embodiment the organometallic compound is applied between layersof conductive polymer.

Subsequent conductive polymer sub-layers, 4²-4^(n), wherein n is up toabout 10, are referred to collectively as the external polymer layer,typically applied in the form of a dispersion or solution, wherein theconductive polymer containing dispersion or solution used to form eachsub-layer may be the same or different thereby resulting in layers whichare compositionally the same or different with a preference forcommonality for manufacturing convenience. At least one external layercomprises the inventive polymer dispersion and preferably each of theexternal layers comprises the inventive polymer dispersion. In oneembodiment the external layers are free of in-situ polymerizedconducting polymer.

The external layers may also independently comprise surface-activesubstances, for example ionic and/or nonionic surfactants; adhesionpromoters, for example organofunctional silanes or hydrolyzates,phosphates thereof, e.g. 3-glycidoxypropyl-trialkoxysilane,3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane,3-methacryloyloxy-propyltrimethoxysilane, vinyltrimethoxysilane oroctyltriethoxysilane, polyurethanes, polyacrylates or polyolefindispersions, or further additives.

The external layers may further independently comprise additives whichenhance the conductivity, for example compounds containing ether groups,for example tetrahydrofuran; compounds containing lactone groups, suchas γ-butyrolactone, valerolactone; compounds containing amide or lactamgroups, such as caprolactam, N-methylcaprolactam, N,N-dimethylacetamide,N-methyl-acetamide, N,N-dimethylformamide (DMF), N-methyl-formamide,N-methylformanilide, N-methylpyrrolidone (NMP), N-octylpyrrolidone,pyrrolidone; sulfones and sulfoxides, for examplesulfolane(tetramethylenesulfone), dimethyl sulfoxide (DMSO); sugars orsugar derivatives, for example sucrose, glucose, fructose, lactose,sugar alcohols, for example sorbitol, mannitol; imides, for examplesuccinimide or maleimide; furan derivatives, for example2-furancarboxylic acid, 3-furancarboxylic acid, and/or di- orpolyalcohols, for example ethylene glycol, glycerol or di- ortriethylene glycol. Preference is given to using, asconductivity-enhancing additives, ethylene glycol, dimethyl sulfoxide,glycerol or sorbitol.

The external polymer layers may have a primer or cross liker layerbetween adjacent conductive polymer sub-layers to improve inter-layeradhesion. In a preferred embodiment conductive polymer sub-layers4²-4^(n) are deposited primer or cross-linker without a primer therebetween. The examples of primer compound are mono amine or diamimecompounds such as comprising at least amine groups and, in oneembodiment, preferably at least 2 amine groups. Diamines which areparticularly suitable amines are listed in U.S. Pat. No. 8,882,856,which is incorporated herein by reference. Specifically preferred aminesinclude crosslinkers which comprise at least one diamine, triamine,oligoamine or polymeric amine or derivatives thereof including thefollowing amines: aliphatic amines, particularly aliphatic .alpha.,.OMEGA.-diamines such as 1,4-diaminocyclohexane or1,4-bis(amino-methyl)cyclohexane; linear aliphatic .alpha.,.OMEGA.-diamines such as ethylenediamine, 1,6-hexanediamine,1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine,1,10-decanediamine or 1,12-dodecanediamine; derivatives of aliphatic.alpha., .OMEGA.-diamines such as N,N-dimethylethylenediamine,N,N,N′,N′-tetramethylethylenediamine,N,N,N′,N′-tetramethyl-1,4-butanediamine,N,N,N,N′,N′,N′-hexamethylhexamethylene-diammonium dibromide, piperazine,1,4-diazabicyclo[2.2.2]octane,N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine,N-[3-(trimethoxysilyl)propyl]ethylenediamine, or1,4-bis(3-aminopropyl)piperazine; amides such asN,N′-diacetyl-1,6-hexanediamine, N,N,N′,N′-tetraacetylethylene-diamine,1,4-diformylpiperazines or N,N′-ethylenebis(stearamide); aliphaticamines having at least three amino groups such as1,4-bis(3-aminopropyl)piperazine; linear aliphatic amines having atleast three amino groups such as N-(6-aminohexyl)-1,6-diaminohexane orN-(3-aminopropyl)-1,4-diaminobutane; derivatives of linear aliphaticamines having at least three amino groups such as3-[2-(2-aminoethylamino) ethylamino]propyltrimethoxysilane; aromaticamines having at least two amino groups, organofunctional silanecontaining amino groups such as 3-aminopropyltriethoxysilane. The primecompound may further comprises strong or weak acid as counter ion suchas p-toluenesulfonic acid, acetic acid, phosphoric acid.

The conductive polymers is selected from the group consisting ofpolyanilines, polypyrroles and polythiophenes each of which may besubstituted. A particularly preferred polymer comprises conjugatedgroups having the structure of Formula 1:

wherein:R¹ and R² independently represent linear or branched C₁-C₁₆ alkyl orC₂-C₁₈ alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzyl which areunsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, halogen orOR³; or R¹ and R², taken together, are linear C₁-C₆ alkylene which isunsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy, halogen,C₃-C₈ cycloalkyl, phenyl, benzyl, C₁-C₄ alkylphenyl, C₁-C₄ alkoxyphenyl,halophenyl, C₁-C₄ alkylbenzyl, C₁-C₄ alkoxybenzyl or halobenzyl, 5-, 6-,or 7-membered heterocyclic structure containing two oxygen elements. R³preferably represents hydrogen, linear or branched C₁-C₁₆ alkyl orC₂-C₁₈ alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzyl which areunsubstituted or substituted by C₁-C₆ alkyl;X is S, N or O and most preferable X is S;R¹ and R² of Formula 1 are preferably chosen to prohibit polymerizationat the β-site of the ring as it is most preferred that only α-sitepolymerization be allowed to proceed; it is more preferred that R¹ andR² are not hydrogen and more preferably, R¹ and R² are α-directors withether linkages being preferable over alkyl linkages; it is mostpreferred that the R¹ and R² are small to avoid steric interferences.

In a particularly preferred embodiment the R¹ and R² of Formula I aretaken together to represent —O—(CHR⁴)_(n)—O— wherein:

n is an integer from 1 to 5 and most preferably 2;

R⁴ is independently selected from hydrogen; a linear or branched C₁ toC₁₈ alkyl radical C₅ to C₁₂ cycloalkyl radical, C₆ to C₁₄ aryl radicalC₇ to C₁₈ aralkyl radical or C₁ to C₄ hydroxyalkyl radical, optionallysubstituted with a functional group selected from carboxylic acid,hydroxyl, amine, substituted amines, alkene, acrylate, thiol, alkyne,azide, sulfate, sulfonate, sulfonic acid, imide, amide, epoxy,anhydride, silane, and phosphate; hydroxyl radical; or R⁴ is selectedfrom —(CHR⁵)_(a)—R¹⁶; —O(CHR⁵)_(a)R¹⁶; CH₂O(CHR⁵)_(a)R¹⁶;—CH₂O(CH₂CHR⁵O)_(a)R¹⁶, orR⁴ is a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, amide, imide, anhydride, hydroxymethyl, alkene,thiol, alkyne, azide, sulfonic acid, benzene sulfonic acidsulfate, SO₃M,anhydride, silane, acrylate and phosphate; R⁵ is H or alkyl chain of 1to 5 carbons optionally substituted with a functional groups selectedfrom carboxylic acid, hydroxyl, amine, alkene, thiol, alkyne, azide,epoxy, acrylate and anhydride;R¹⁶ is H or SO₃M or an alkyl chain of 1 to 5 carbons optionallysubstituted with a functional groups selected from carboxylic acid,hydroxyl, amine, substituted amines, alkene, thiol, alkyne, azide,amide, imide, sulfate, SO₃M, amide, epoxy, anhydride, silane, acrylateand phosphate;a is integer from 0 to 10; andM is a H or cation preferably selected from ammonia, sodium orpotassium.

The conducting polymer can be either a water-soluble orwater-dispersible compound. Examples of such a π conjugated conductivepolymer include polypyrrole or polythiophene. Particularly preferredconductive polymers include poly(3,4-ethylenedioxythiophene),poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxy)-1-butane-sulphonicacid, salt),poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxy)-1-propane-sulphonicacid, salt),poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxy)-1-methyl-1-propane-sulphonicacid, salt), poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxyalcohol, poly(N-methylpyrrole), poly(3-methylpyrrole),poly(3-octylpyrrole), poly(3-decylpyrrole), poly(3-dodecylpyrrole),poly(3,4-dimethylpyrrole), poly(3,4-dibutylpyrrole),poly(3-carboxypyrrole), poly(3-methyl-4-carboxypyrrole),poly(3-methyl-4-carboxyethylpyrrole),poly(3-methyl-4-carboxybutylpyrrole), poly(3-hydroxypyrrole),poly(3-methoxypyrrole), polythiophene, poly(3-methylthiophene),poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene),poly(3-decylthiophene), poly(3-dodecylthiophene),poly(3-ociadecylthiophene), poly(3-bromothiophene),poly(3,4-dimethylthiophene), poly(3,4-dibutylthiophene),poly(3-hydroxythiophene), poly(3-methoxythiophene),poly(3-ethoxythiophene), poly(3-butoxythiophene),poly(3-hexyloxythiophene), poly(3-heptyloxythiophene),poly(3-octyloxythiophene), poly(3-decyloxythiophene),poly(3-dodecyloxythiophene), poly(3-octadecyloxythiophene),poly(3,4-dihydroxythiophene), poly(3,4-dimethoxythiophene),poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene),poly(3,4-butenedioxythiophene), poly(3-carboxythiophene),poly(3-methyl-4-carboxythiophene),poly(3-methyl-4-carboxyeihylthiophene),poly(3-methyl-4-carboxybutylihiophene), polyaniline,poly(2-methylaniline), poly(3-isobutylaniline), poly(2-anilinesulfonate), poly(3-aniline sulfonate), and the like.

Co-polymers composed at least two different copolymerized monomers arecontemplated. Co-polymers comprise at least one polymerized monomerselected from the group consisting of polypyrrole, polythiophene,poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxy)-1-butane-sulphonicacid, salt),poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxy)-1-methyl-1-propane-sulphonicacid, salt), poly(N-methylpyrrole), poly(3-methylthiophene),poly(3-methoxythiophene), and poly(3,4-ethylenedioxythiophene).

A particularly preferred polymer is poly-3,4-polyethylene dioxythiophene(PEDOT).

The polyanion in at least bimodal conductive particles is a homopolymerof polystyrenesulfonic acid or salt of polystyrenesulfonate, and/orrandom copolymer comprising groups A, B and C represented by the ratioof Formula 2:A_(x)B_(y)C_(z)   Formula 2wherein:A is polystyrenesulfonic acid or salt of polystyrenesulfonate;B and C separately represent polymerized units substituted with a groupselected from:-Carboxyl groups;—C(O)OR⁶ wherein R⁶ is selected from the group consisting of:

-   -   an alkyl of 1 to 20 carbons optionally substituted with a        functional group selected from the group consisting of hydroxyl,        carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene,        alkyne, azide, phosphate, acrylate, anhydride and        -   (CHR⁷CH₂O)_(b)—R⁸ wherein:        -   R⁷ is selected from a hydrogen or an alkyl of 1 to 7 carbons            and preferably hydrogen or methyl;        -   b is an integer from 1 to the number sufficient to provide a            molecular weight of up to 200,000 for the —CHR⁷CH₂O— group;            and        -   R⁸ is selected from the group consisting of hydrogen,            silane, phosphate, acrylate, an alkyl of 1 to 9 carbons            optionally substituted with a functional group selected from            the group consisting of hydroxyl, carboxyl, amine, epoxy,            silane, amide, imide, thiol, alkene, alkyne, phosphate,            azide, acrylate, and anhydride;            —C(O)—NHR⁹ wherein:    -   R⁹ is hydrogen or an alkyl of 1 to 20 carbons optionally        substituted with a functional group selected from the group        consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,        imide, thiol, alkene, alkyne, phosphate, azide, acrylate and        anhydride;        —C₆H₄—R¹⁹ wherein:    -   R¹⁹ is selected from:    -   a hydrogen or alkyl optionally substituted with a functional        group selected from the group consisting of hydroxyl, carboxyl,        amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,        phosphate, azide, acrylate and anhydride;    -   a reactive group selected from the group consisting of hydroxyl,        carboxyl, amine, epoxy, silane, imide, amide, thiol, alkene,        alkyne, phosphate, azide, acrylate, anhydride and    -   —(O(CHR¹¹CH₂O)_(d)—R¹² wherein:    -   R¹¹ is a hydrogen or an alkyl of 1 to 7 carbons and preferably        hydrogen or methyl;    -   d is an integer from 1 to the number sufficient to provide a        molecular weight of up to 200,000 for the —CHR¹¹CH₂O— group;    -   R¹² is selected from the group consisting of hydrogen, an alkyl        of 1 to 9 carbons optionally substituted with a functional group        selected from the group consisting of hydroxyl, carboxyl, amine,        epoxy, silane, amide, imide, thiol, alkene, alkyne, phosphate,        azide, acrylate and anhydride;        —C₆H₄—O—R¹³ wherein:    -   R¹³ is selected from:    -   a hydrogen or an alkyl optionally substituted with a reactive        group selected from the group consisting of hydroxyl, carboxyl,        amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,        azide, acrylate, phosphate and anhydride;    -   a reactive group selected from the group consisting of epoxy,        silane, alkene, alkyne, acrylate, phosphate and    -   —(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:    -   R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons and preferably        hydrogen or methyl;    -   e is an integer from 1 to the number sufficient to provide a        molecular weight of up to 200,000 for the —CHR¹⁴CH₂O— group; and    -   R¹⁵ is selected from the group consisting of hydrogen and an        alkyl of 1 to 9 carbons optionally substituted with a functional        group selected from the group consisting of hydroxyl, carboxyl,        amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,        azide, acrylate, phosphate and anhydride;    -   x, y and z, taken together are sufficient to form a polyanion        with a molecular weight of at least 100 to no more than 500,000        and y/x is 0 to 100 more preferably 0.01 to 100; z is 0 to a        ratio z/x of no more than 100; more preferably x represents        50-99%, y represents 1 to 50% and z represents 0 to 49% of the        sum total of x+y+z; even more preferably x represents 70-90%; y        represents 10 to 30% and z represents 0 to 20% of the sum total        of x+y+z.

A particular feature of the instant invention is the ability to adjustthe ratio of conductive polymer to polyanion for the different particlesizes due to the difference in surface area and size. It is preferredthat the molar ratio of conductive polymer to polyanion for each of thesmaller particle size portion and the larger size portion be in therange of 1:0.1 to 0.1:1, more preferably 1:1 to 0.2:1 and even morepreferably 0.8:1 to 0.25:1. In an embodiment the molar ratio ofconductive polymers to polyanion is higher for the first particles,having a larger average diameter, than in the second particles havingthe smaller average diameter. More preferably, the molar ratio ofconductive polymers to polyanion is 10% larger for the smaller particlesize portion than in the larger particle size portion. Without beinglimited to theory, the increased molar ratio for the smaller particlesizes improves the interparticle packing in the coating therebyimproving the quality of the coating, particularly, on the edges andcorners.

Another particular feature of the invention is the ability to adjust themolecular weight of the polyanion for the two portions of the dispersionhaving different particle sizes. The preferred molecular weight ofpolyanion for each of the smaller particle size portion of thedispersion and the larger particle size portion of the dispersion is atleast about 600 to no more than about 500,000. In an embodiment thepolyanion can have a different molecular weight for the large particlesize portion than for the small particle size portion.

The dispersion of particles of conductive polymer and polyanion havingmultiple particle sizes is preferably formed by high shearpolymerization with a rotor-stator system at high solids content such asabove about 3 wt % of mixture of monomer and polyanion. While notlimited to theory it is hypothesized that a combination of the monomerconcentration and high shear kinetics facilitates the growth ofparticles having a mixture of particle sizes. High shear rotor-statorpolymerization is described in U.S. Pat. No. 9,030,806 which isincorporated herein by reference. In one embodiment a portion of thedispersion is further subjected to rotor-stator high shear mixing,ultrasonic mixing, acoustic mixing, high-pressure homogenizer or a highshearing homogenizer.

However, the preparation of dispersion with particles of conductivepolymer and polyanion having a mixture of sizes may be prepared by othermethods, including mixing, and may not be limited to high shearrotor-stator polymerization.

A particular feature of the inventive dispersion is the decreasedviscosity relative to monomodal dispersions at a given percent solidsloading for the dispersion. The lower viscosity, at higher solidscontent, improves the coating quality especially at the edges andcorners of the anodized anode. The inventive dispersion with multipleparticle sizes has a viscosity of at least 2000 cP at 6 rpm to no morethan 5000 cP at 6 rpm when polymerized at 3.56% solids input of mixtureof monomer and polyanion during polymerization. With monomodal sizedparticles the viscosity is above 6000 cP at 6 rpm when polymerized with2.1% solids input of monomer and polyanion and increases with increased% solids input. The ability to apply a dispersion with higher percentsolids at low viscosity is advantageous for improved coating quality.

The dispersion of conducting polymer with an at least bimodal particlesize distribution may further comprise a polymeric dopant. A preferredpolymeric dopant is polystyrene sulfonate (PSS). Polystyrene sulfonicacid (PSSA) copolymer is a particularly preferred dopant particularly asa copolymer with polyethylene glycol monoacrylate.

The conductive polymer solution or dispersion preferably comprisesreactive monomers as film formers which can improve polymer filmstrength upon drying of the film. The reactive monomer or oligomers canbe soluble in water or organic solvent or disperse in water through theuse of ionic/non-ionic surfactants. The reactive monomers can haveaverage functionalities of at least two or more. The curing process ofthe monomer can be catalyzed by using heat, radiation or chemicalcatalysis. Exemplary monomers include compounds having more than oneepoxy group includes ethylene glycol diglycidyl ether (EGDGE), propyleneglycol diglycidyl ether (PGDGE), 1,4-butanediol diglycidyl ether(BDDGE), pentylene glycol diglycidyl ether, hexylene glycol diglycidylether, cyclohexane dimethanol diglycidyl ether, resorcinol glycidylether, glycerol diglycidyl ether (GDGE), glycerol polyglycidyl ethers,diglycerol polyglycidyl ethers, trimethylolpropane polyglycidyl ethers,sorbitol diglycidyl ether (Sorbitol-DGE), sorbitol polyglycidyl ethers,polyethylene glycol diglycidyl ether (PEGDGE), polypropylene glycoldiglycidyl ether, polytetramethylene glycol diglycidyl ether,di(2,3-epoxypropyl) ether, 1,3-butadiene diepoxide, 1,5-hexadienediepoxide, 1,2,7,8-diepoxyoctane, 1,2,5,6-diepoxycyclooctane, 4-vinylcyclohexene diepoxide, bisphenol A diglycidyl ether, maleimide-epoxycompounds, diglycidyl ether, glycidyl acrylate, glycidyl methacrylate,bisphenol A epoxy, epoxidized Bisphenol A novolac modified epoxy,urethane modified Bisphenol A epoxy, an epoxidized o-cresylic novolacand so forth.

Additional film formers are monomers containing acidic groups. Exemplaryacidic monomers include: oxalic acid, malonic acid, succinic acid,glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid,sebacic acid, dodecanedioic acid, phthalic acids, maleic acid, muconicacid, citric acid, trimesic acid, polyacrylic acid, etc. Particularlypreferred organic acids are aromatic acid such as phthalic acid, andparticularly ortho-phthalic acid.

Film forming monomers containing alcohol/acrylate groups can beemployed. Exemplary monomers include: diethylene glycol,pentaerythritol, triethylene glycol, oligo/polyethylene glycol,triethylene glycol monochlorohydrin, diethylene glycol monochlorohydrin,oligo ethylene glycol monochlorohydrin, triethylene glycolmonobromohydrin, diethylene glycol monobromohydrin, oligo ethyleneglycol monobromohydrin, polyethylene glycol, polyether, polyethyleneoxide, triethylene glycol-dimethylether, tetraethyleneglycol-dimethylether, diethylene glycol-dimethylether, diethyleneglycol-diethylether-diethylene glycol-dibutylether, dipropylene glycol,tripropylene glycol, polypropylene glycol, polypropylene dioxide,polyoxyethylene alkylether, polyoxyethylene glycerin fatty acid ester,polyoxyethylene fatty acid amide, 2-hydroxyethyl methacrylate,2-hydroxypropyl methacrylate, n-butoxyethyl methacrylate,n-butoxyethylene glycol methacrylate, methoxytriethylene glycolmethacrylate, methoxypolyethylene glycol methacrylate, 2-hydroxyethylacrylate, 2-hydroxypropyl acrylate, n-butoxyethyl acrylate,n-butoxyethylene glycol acrylate, methoxytriethylene glycol acrylate,methoxypolyethylene glycol acrylate, and the like; bifunctional(meth)acrylate compounds, such as, ethylene glycol di(meth)acrylate,diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate,polyethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate,glycerin di(meth)acrylate, and the like; glycidyl ethers, such as,ethylene glycol diglycidyl ether, glycidyl ether, diethylene glycoldiglycidyl ether, triethylene glycol diglycidyl ether, polyethyleneglycol diglycidyl ether, propylene glycidyl ether, tripropylene glycidylether, polypropylene glycidyl ether, glycerin diglycidyl ether, and thelike; glycidyl methacrylate, trimethylolpropane triacrylate, ethyleneoxide-modified trimethylolpropane triacrylate, ethylene oxide-modifiedpentaerythritol triacrylate, ethylene oxide-modified pentaerythritoltetraacrylate, and the like.

The external polymer layers may also independently comprise film formingpolyanions containing reactive groups such as epoxy, alcohol, silanes,phosphates, amine, alkene, thiol, alkyne, azide carboxylic acid.

The external polymer layers may also independently comprise, as filmformers, linear hyperbranched polymers described in U.S. Pat. No.9,378,898. The external polymer layer may comprise alinear-hyperbranched polymer where the linear block has at least tworeactive end functional groups selected from hydroxyl groups, aminogroups, epoxy, acrylate, acid etc. and where the hyper-branched blockcomprises polyether-epoxy, polyester-epoxy, polyester-silanol,polyester-acid, polyether-alcohol, polyimide-acid, polyether-acrylate,polyether-silanol and polyester-amine pendant groups.

The external polymer layers may further independently comprise workfunction modifiers described in U.S. Publ. Appl. No. 20150348715.Exemplary work function modifiers include organotitanate derivativespreferably selected from the group consisting of di-alkoxy acyltitanate, tri-alkoxy acyl titanate, alkoxy triacyl titantate, alkoxytitantate, neoalkoxy titanate, titanium IV 2,2(bis2-propenolatomethyl)butanolato, tris neodecanoato-O; titanium IV 2,2(bis2-propenolatomethyl)butanolato, iris(dodecyl)benzenesulfonato-O;titanium IV 2,2(bis 2-propenolatomethyl)butanolato,tris(dioctyl)phosphato-O; titanium IV 2,2(bis2-propenolatomethyl)tris(dioctyl)pyrophosphatobutanolato-O; titanium IV2,2(bis 2-propenolatomethyl)butanolato, tris(2-ethylenediamino)ethylato;and titanium IV 2,2(bis 2-propenolatomethyl)butanolato,tris(3-amino)phenylato being representative neoalkoxy titanates andderivatives thereof. Furthermore, the work function modifier can be acompound selected from the group consisting of cycloaliphatic epoxyresin, ethylene glycol diglycidyl ether, bisphenol A epoxy resin,bisphenol F epoxy resin, bisphenol S epoxy resin, novolac epoxy resin,aliphatic epoxy resin, glycidylamine epoxy resin, ethylene glycoldiglycidyl ether (EGDGE), propylene glycol diglycidyl ether (PGDGE),1,4-butanediol diglycidyl ether (BDDGE), pentylene glycol diglycidylether, hexylene glycol diglycidyl ether, cyclohexane dimethanoldiglycidyl ether, resorcinol glycidyl ether, glycerol diglycidyl ether(GDGE), glycerol polyglycidyl ethers, diglycerol polyglycidyl ethers,trimethylolpropane polyglycidyl ethers, sorbitol diglycidyl ether(Sorbitol-DGE), sorbitol polyglycidyl ethers, polyethylene glycoldiglycidyl ether (PEGDGE), polypropylene glycol diglycidyl ether,polytetramethylene glycol diglycidyl ether, di(2,3-epoxypropyl)ether,1,3-butadiene diepoxide, 1,5-hexadiene diepoxide, 1,2,7,8-diepoxyoctane,1,2,5,6-diepoxycyclooctane, 4-vinyl cyclohexene diepoxide, bisphenol Adiglycidyl ether, maleimide-epoxy compounds, and derivatives thereof.

External polymer layers may further independently comprise nonionicpolymers such as a hydroxy-functional nonionic polymer. The term“hydroxy-functional” generally means that the compound contains at leastone hydroxyl functional group. The molecular weight of thehydroxy-functional polymer may be from about 100 to 10,000 grams permole, in some embodiments from about 200 to 2.000, in some embodimentsfrom about 300 to about 1,200, and in some embodiments, from about 400to about 800.

Any of a variety of hydroxy-functional nonionic polymers may generallybe employed. In one embodiment, for example, the hydroxy-functionalpolymer is a polyalkylene ether. Polyalkylene ethers may includepolyalkylene glycols such as polyethylene glycols, polypropylene glycolspolytetramethylene glycols, polyepichlorohydrins; polyoxetanes,polyphenylene ethers, polyether ketones, and the like. Polyalkyleneethers are typically predominantly linear, nonionic polymers withterminal hydroxy groups. Particularly suitable are polyethylene glycols,polypropylene glycols and polytetramethylene glycols(polytetrahydrofurans). The diol component may be selected, inparticular, from saturated or unsaturated, branched or unbranched,aliphatic dihydroxy compounds containing 5 to 36 carbon atoms oraromatic dihydroxy compounds, such as, for example, pentane-1,5-diol,hexane-1,6-diol, neopentyl glycol, bis-(hydroxymethyl)-cyclohexanes,bisphenol A, dimer diols, hydrogenated dimer diols or even mixtures ofthe diols mentioned.

In addition to those noted above, other hydroxy-functional nonionicpolymers may also be employed. Some examples of such polymers include,for instance, ethoxylated alkylphenols; ethoxylated or propoxylatedC₆-C₂₄ fatty alcohols; polyoxyethylene glycol alkyl ethers having thegeneral formula: CH₃—(CH₂)₁₀₋₁₆—(O—C₂H₄)₁₋₂₅—OH (e.g., octaethyleneglycol monododecyl ether and pentaethylene glycol monododecyl ether);polyoxypropylene glycol alkyl ethers having the general formula:CH₃—(CH₂)₁₀₋₁₆—(O—C₃H₆)₁₋₂₅—OH; polyoxyethylene glycol octylphenolethers having the following general formula:C₈—H₁₇—(C₆H₄)—(O—C₂H₄)₁₋₂₅—OH (e.g., Triton™ X-100); polyoxyethyleneglycol alkylphenol ethers having the following general formula:C₉—H₁₉—(C₆H₄)—(O—C₂H₄)₁₋₂₅—OH (e.g., nonoxynol-9); polyoxyethyleneglycol esters of C₈−C₂₁ fatty acids, such as polyoxyethylene glycolsorbitan alkyl esters (e.g., polyoxyethylene (20) sorbitan monolaurate,polyoxyethylene (20) sorbitan monopalmitate, polyoxyethylene (20)sorbitan monostearate, polyoxyethylene (20) sorbitan monooleate, PEG-20methyl glucose distearate, PEG-20 methyl glucose sesquistearate, PEG-80castor oil, and PEG-20 castor oil, PEG-3 castor oil, PEG 600 dioleate,and PEG 400 dioleate) and polyoxyethylene glycerol alkyl esters (e.g.,polyoxyethylene-23 glycerol laurate and polyoxyethylene-20 glycerolstearate); polyoxyethylene glycol ethers of C₈-C₂₄ fatty acids (e.g.,polyoxyethylene-10 cetyl ether, polyoxyethylene-10 stearyl ether,polyoxyethylene-20 cetyl ether, polyoxyethylene-10 oleyl ether,polyoxyethylene-20 oleyl ether, polyoxyethylene-20 isohexadecyl ether,polyoxyethylene-15 tridecyl ether, and polyoxyethylene-6 tridecylether); block copolymers of polyethylene glycol and so forth.

The conductive polymer solution or dispersion may have a pH of 1 to 14,preference being given to a pH of 1 to 10, particularly preferred is apH of 1 to 8 with the pH being measured at 25° C. To adjust the pH,bases or acids, for example, can be added to the solutions ordispersions. The bases used may be inorganic bases, for example sodiumhydroxide, potassium hydroxide, calcium hydroxide or ammonia, or organicbases, for example ethylamine, diethylamine, triethylamine, propylamine,dipropylamine, tripropylamine, isopropylamine, diisopropylamine,butylamine, dibutylamine, tributylamine, isobutylamine, diisobutylamine,triisobutylamine, 1-methylpropylamine, methylethylamine,bis(1-methyl)propylamine, 1,1-dimethylethylamine, pentylamine,dipentylamine, tripentylamine, 2-pentylamine, 3-pentylamine,2-methyl-butylamine, 3-methylbutylamine, bis(3-methyl-butylamine)methylbutylamine), hexylamine, octylamine, 2-ethylhexylamine,decylamine, N-methyl-butylamine, N-ethylbutylamine,N,N-dimethylethylamine, N,N-dimethylpropyl, N-ethyldiisopropylamine,allylamine, diallylamine, ethanolamine, diethanolamine, triethanolamine,methylethanolamine, methyl-diethanolamine, dimethylethanolamine,diethyl-ethanolamine, N-butylethanolamine, N-butyldiethanol-amine,dibutylethanolamine, cyclohexylethanolamine, cyclohexyldiethanolamine,N-ethylethanolamine, N-propylethanolamine, tert-butylethanolamine,tert-butyl-diethanolamine, propanolamine, dipropanolamine,tripropanolamine or benzylamine, bi-, tri-, or tetra-functional amines.The acids used may be inorganic acids, for example sulfuric acid,phosphoric acid or nitric acid, or organic acids, for example carboxylicor sulfonic acids.

The process for forming a capacitor will be described with reference toFIG. 2 wherein the process is represented schematically. In FIG. 2,droplets of monomer are formed in monomer solution comprising at least 3wt % monomer and polyanion to no more than 10 wt % monomer and polyanionat 100 preferably by a stator rotor. The droplets are then polymerizedby high shear polymerization preferably in the presence of polyanionthereby forming a polymer dispersion at 102 wherein the polymerdispersion comprises at least a bimodal size distribution of conductingpolymer/polyanion particles. An anode is prepared at 104 wherein theanode is a conductor, and preferably a valve metal. A dielectric isformed on the anode at 106 wherein the preferred dielectric is an oxideof the anode. A conductive polymer layer of the polymer is formed on thedielectric at 108 thereby forming a conductive couple with a dielectricthere between. At least one layer of the conductive polymer layer isformed by application of the dispersion comprising the conductivepolymer/polyanion particles in at least a bimodal size distribution. Thedispersion is preferably applied by dipping. In a preferred embodimentan internal polymer layer is formed prior to application of thedispersion comprising the conductive polymer/polyanion particles in atleast a bimodal size distribution. The capacitor is finished at 110wherein finishing can include but is not limited to testing, formingexternal terminations, encapsulating and the like.

The anode material is not limited herein. A particularly preferred anodematerial is a metal and a particularly preferred metal is a valve metalor a conductive oxide of a valve metal. Particularly preferred anodesinclude niobium, aluminum, tantalum and NbO without limit thereto.

The dielectric is not particularly limited herein. A particularlypreferred dielectric is an oxide of the anode due to manufacturingconsiderations.

Throughout the description terms such as “alkyl”, “aryl”, “alkylaryl”,“arylalkyl” refer to unsubstituted or substituted groups and if alreadylisted as substituted, such as “alkyl alcohol” refer to groups which arenot further substituted or may be further substituted.

Test Methods

Corners and Edge Coverage Measurement

Corner and edge coverage of conducting polymer dispersions on ananodized anode in solid electrolytic capacitors was inspected under amicroscope and scaled per the following criteria: corners and edges notcovered 85%, edges covered and corners not covered 90%, edges coveredand half of corners covered 95%; corners and edges appear completelycovered 100%.

Particle Size Analysis

The particle size of conducting polymer:polyanion complex particles wasmeasured using a disk centrifuge particle size analyzer from CPSinstruments. A diameter distribution of the particles relates to aweight distribution of the particles in the dispersion as a function ofthe particle diameter. In this context, the D₁₀ value of the diameterdistribution states that 10% of the total weight of all the particles ofconductive polymer polyanion complex in the dispersion can be assignedto particles which have a diameter of less than or equal to the D₁₀value. The D₅₀ value of the diameter distribution states that 50% of thetotal weight of all the particles of conductive polymer in thedispersion can be assigned to particles which have a diameter of lessthan or equal to the D₅₀ value. The D₉₀ value of the diameterdistribution states that 90% of the total weight of all the particles ofconductive polymer in the dispersion can be assigned to particles whichhave a diameter of less than or equal to the D₉₀ value.

EXAMPLES Example 1

Poly(4-styrenesulfonic acid-co-poly(ethylene glycol) methacrylate)sodium salt was synthesized. A 500 ml flask was initially charged with33 ml deionized water as a solvent. After adding 8 g styrenesulfonicacid sodium salt, 2 g poly(ethylene glycol) methyl ether methacrylate(Mn 480) and 1 g ammonium persulfate, the mixture was saturated withnitrogen by means of a gas inlet tube. Nitrogen was passed through themixture for 15 min. and during this time, the mixture was heated to 80°C. The flask was sealed with a rubber septum and the solution wasallowed to polymerize for 16 hours. The resulting polyanion copolymerwas acidified with dilute sulfuric acid and used directly forpreparation of conducting polymer dispersion.

Example 2

The conductive polymer dispersion was synthesized by high shearpolymerization. 1740 g of DI water and 166 g of PSSA 30% (Alfa Aesar)were charged into a 4 L polyethylene bottle. The reaction solution waspurged with nitrogen for 0.5-1 hr. The contents were mixed using arotor-stator mixing system with perforated stator screen with a roundhole diameter of 1.5 mm. Subsequently, 57 g of 1% ferric sulfatesolution and 43 g of sodium persulfate were then added into the reactionmixture, followed by dropwise addition of 22.5 g of3,4-ethylenedioxythiophene (EDOT) (Baytron M from Heraeus). The reactionmixture containing 3.56% solids of monomer and polyanion was shearedcontinuously with a shear speed at 4200 rpm for 24 hours. 600 g ofLewatit S108H and 600 g of Lewatit MP62WS ion exchange resins were addedinto the slurry and rolled at around 60 rpm overnight. The conductivepolymer dispersion was separated from resins by filtration. Theresulting poly(3,4-ethylenedioxythiophene)/polystyrene sulfonic aciddispersion had a bimodal particle size distribution with second particlehaving a D₅₀ particle size of 350 nm and first particle having a D₅₀particles size of 3.50 micron.

Example 2-1

The conducting polymer dispersion prepared as per procedure in example 2was further homogenized with an ultrasonicator. The resulting dispersionalso has bimodal particle size distribution with D₅₀ of 25 nm and 75 nm.

Example 3

1740 g of DI water and 166 g of polyanion copolymer (30%) from Example 1were charged into a 4 L polyethylene bottle. The reaction solution waspurged with nitrogen for 0.5-1 hr. The contents were mixed using arotor-stator mixing system with perforated stator screen with a roundhole diameter of 1.5 mm. Subsequently, 57 g of 1% ferric sulfatesolution and 43 g of sodium persulfate were then added into the reactionmixture, followed by dropwise addition of 22.5 g of3,4-ethylenedioxythiophene (EDOT) (Baytron M from Heraeus). The reactionmixture containing 3.56% solids of monomer and polyanion was shearedcontinuously with a shear speed at 4200 rpm for 24 hours. 600 g ofLewatit S108H and 600 g of Lewatit MP62WS ion exchange resins were addedinto the slurry and rolled at around 60 rpm overnight. The conductivepolymer dispersion was separated from resins by filtration. Theresulting poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonicacid-co-poly(ethylene glycol) methacrylate) dispersion had a bimodalparticle size distribution with second particle having a D₅₀ particlessize of 250 nm and first particle having a D₅₀ particles size of 3.50micron.

Example 3-1

The conducting polymer dispersion prepared as per procedure in example 3was further homogenized with an ultrasonicator. The resulting dispersionalso has bimodal particle size distribution with D₅₀ of 20 nm and 65 nm.

Example 4

2805 g of DI water and 336 g of polyanion copolymer (40%) from Example 1were charged into a 4 L polyethylene bottle. The reaction solution waspurged with nitrogen for 0.5-1 hr. The contents were mixed using arotor-stator mixing system with perforated stator screen with a roundhole diameter of 1.5 mm. Subsequently, 141.3 g of 1% ferric sulfatesolution and 106.65 g of sodium persulfate were then added into thereaction mixture, followed by dropwise addition of 22.5 g of3,4-ethylenedioxythiophene (EDOT) (Baytron M from Heraeus). The reactionmixture containing 5.20% solids of monomer and polyanion was shearedcontinuously with a shear speed at 4200 rpm for 24 hours. 1486 g ofLewatit S108H and 1486 g of Lewatit MP62WS ion exchange resins wereadded into the slurry and rolled at around 60 rpm overnight. Theconductive polymer dispersion was separated from resins by filtration.The resulting poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonicacid-co-poly(ethylene glycol) methacrylate) dispersion had a bimodalparticle size distribution with first particle having a D₅₀ particlessize of 3.50 micron and second particle having a D₅₀ particles size of300 nm.

Comparative Example 1

2531 g of DI water and 125 g of PSSA 30% (Alfa Aesar) were charged intoa 4 L polyethylene bottle. The reaction solution was purged withnitrogen for 0.5-1 hr. The contents were mixed using a rotor-statormixing system with perforated stator screen with a round hole diameterof 1.5 mm. Subsequently, 28.5 g of 1% ferric sulfate solution and 21.5 gof sodium persulfate were then added into the reaction mixture, followedby dropwise addition of 11.25 g of 3,4-ethylenedioxythiophene (EDOT)(Baytron M from Heraeus). The reaction mixture containing 1.79% solidsof monomer and polyanion was sheared continuously with a shear speed at4200 rpm for 24 hours. 300 g of Lewatit S108H and 300 g of LewatitMP62WS ion exchange resins were added into the slurry and rolled ataround 60 rpm overnight. The conductive polymer dispersion was separatedfrom resins by filtration. The resultingpoly(3,4-ethylenedioxythiophene)/polystyrene sulfonic acid dispersionhad a monomodal particle size distribution with a D₅₀ particles size of110 nm.

Comparative Example 2

2531 g of DI water and 125 g of polyanion copolymer (30%) from Example 1were charged into a 4 L polyethylene bottle. The reaction solution waspurged with nitrogen for 0.5-1 hr. The contents were mixed using arotor-stator mixing system with perforated stator screen with a roundhole diameter of 1.5 mm. Subsequently, 28.5 g of 1% ferric sulfatesolution and 21.5 g of sodium persulfate were then added into thereaction mixture, followed by dropwise addition of 11.25 g of3,4-ethylenedioxythiophene (EDOT) (Baytron M from Heraeus). The reactionmixture containing 1.79% solids of monomer and polyanion was shearedcontinuously with a shear speed at 4200 rpm for 24 hours. 300 g ofLewatit S108H and 300 g of Lewatit MP62WS ion exchange resins were addedinto the slurry and rolled at around 60 rpm overnight. The conductivepolymer dispersion was separated from resins by filtration. Theresulting poly(3,4-ethylenedioxythiophene/poly(4-styrenesulfonicacid-co-poly(ethylene glycol) methacrylate) dispersion had a monomodalparticle size distribution with a D₅₀ particle size of 80 nm.

Example 5

Conducting polymer dispersions from Example 2 were mixed with DMSO,3-glycidoxypropyltrimethoxysilane and reactive monomer/oligomercontaining at least three epoxy groups followed by mixing on rollerovernight.

Example 6

Conducting polymer dispersions from Example 3 were mixed with DMSO,3-glycidoxypropyltrimethoxysilane and reactive monomer/oligomercontaining at least three epoxy groups followed by mixing on rollerovernight.

Example 6-1

Conducting polymer dispersions formulated in same manner as example 6except mixture of conducting polymer dispersion from example 3 andexample 3-1 in ratio of 2:8 were used.

Comparative Example 3

Conducting polymer dispersions from comparative Example 1 were mixedwith DMSO, 3-glycidoxypropyltrimethoxysilane and reactive monomerscontaining two epoxy and two carboxylic groups followed by mixing onroller overnight.

Comparative Example 4

Conducting polymer dispersions from comparative Example 2 were mixedwith DMSO, 3-glycidoxypropyltrimethoxysilane and reactivemonomer/oligomer containing at least three epoxy groups followed bymixing on roller overnight.

Example 7

Solid electrolytic capacitors were prepared by standard techniques. Aseries of tantalum anodes (33 microfarads, 35V) were prepared. Thetantalum was anodized to form a dielectric on the tantalum anode. Theanodes thus formed were dipped into a solution of iron (III)toluenesulfonate oxidant for 1 minute and sequentially dipped intoethyldioxythiophene monomer for 1 minute to form a thin layer ofconductive polymer (PEDOT) on the dielectric of the anodized anodes. Theanodized anodes were washed to remove excess monomer and by-products ofthe reactions after the completion of 60 minutes of polymerization. Thisprocess was repeated until a sufficient thickness was achieved.Conductive polymer dispersion from Example 5 was applied andsubsequently dried to form an external polymer layer. This process wererepeated 4 times. The parts were inspected under microscope for cornersand edge coverage. A sequential coating of a graphite layer and a silverlayer were applied to produce a solid electrolytic capacitor. Parts wereassembled and packaged.

Inventive Example 8

A series of tantalum anodes (33 microfarads, 35V) were prepared. Thetantalum were anodized to form a dielectric on the tantalum anode. Theanodes thus formed was dipped into a solution of iron (III)toluenesulfonate oxidant for 1 minute and sequentially dipped intoethyldioxythiophene monomer for 1 minute to form an a thin layer ofconductive polymer (PEDOT) on the dielectric of the anodized anodes. Theanodized anodes were washed to remove excess monomer and by-products ofthe reactions after the completion of 60 minutes of polymerization. Thisprocess was repeated until a sufficient thickness was achieved.Conductive polymer dispersion from Example 6 was applied andsubsequently dried to form an external polymer layer. This process wererepeated 4 times. The parts were inspected under microscope for cornersand edge coverage. A sequential coating of a graphite layer and a silverlayer were applied to produce a solid electrolytic capacitor. Parts wereassembled and packaged.

Inventive Example 8-1

A solid electrolytic capacitor were produced in same manner as shown ininventive example 8 except conductive polymer dispersion from Example6-1 was used.

Inventive Example 8-2

A solid electrolytic capacitor were produced in same manner as shown ininventive example 8-1 except internal layer was formed bypre-polymerized conductive polymer.

Inventive Example 8-3

A solid electrolytic capacitor were produced in same manner as shown ininventive example 8-2 except organometalic compound was applied betweendielectric and pre-polymerized conducting polymer.

Inventive Example 8-4

A solid electrolytic capacitor were produced in same manner as shown ininventive example 8-3 except cross-linker solution was applied betweenexternal polymer layers.

Inventive Example 8-5

A solid electrolytic capacitor were produced in same manner as shown ininventive example 8-3 except cross-linker or primer solution was appliedbetween internal polymer layer and external polymer.

Comparative Example 5

A series of tantalum anodes (33 microfarads, 35V) were prepared. Thetantalum was anodized to form a dielectric on the tantalum anode. Theanodes thus formed was dipped into a solution of iron (III)toluenesulfonate oxidant for 1 minute and sequentially dipped intoethyldioxythiophene monomer for 1 minute to form a thin layer ofconductive polymer (PEDOT) on the dielectric of the anodized anodes. Theanodized anodes were washed to remove excess monomer and by-products ofthe reactions after the completion of 60 minutes of polymerization. Thisprocess was repeated until a sufficient thickness was achieved.Conductive polymer dispersion from comparative Example 3 was applied andsubsequently dried to form an external polymer layer. This process wererepeated 4 times. The parts were inspected under microscope for cornersand edge coverage. A sequential coating of a graphite layer and a silverlayer were applied to produce a solid electrolytic capacitor. Parts wereassembled and packaged.

Comparative Example 6

A series of tantalum anodes (33 microfarads, 35V) were prepared. Thetantalum was anodized to form a dielectric on the tantalum anode. Theanodes thus formed were dipped into a solution of iron (III)toluenesulfonate oxidant for 1 minute and sequentially dipped intoethyldioxythiophene monomer for 1 minute to form an a thin layer ofconductive polymer (PEDOT) on the dielectric of the anodized anodes. Theanodized anodes were washed to remove excess monomer and by-products ofthe reactions after the completion of 60 minutes of polymerization. Thisprocess was repeated until a sufficient thickness was achieved.Conductive polymer dispersion from Comparative Example 4 was applied andsubsequently dried to form an external polymer layer. This process wasrepeated 4 times. The parts were inspected under microscope for cornersand edge coverage. A sequential coating of a graphite layer and a silverlayer were applied to produce a solid electrolytic capacitor. Parts wereassembled and packaged.

Comparative Example 7

A series of tantalum anodes (33 microfarads, 35V) were prepared. Thetantalum was anodized to form a dielectric on the tantalum anode. Theanodes thus formed were dipped into a solution of iron (III)toluenesulfonate oxidant for 1 minute and sequentially dipped intoethyldioxythiophene monomer for 1 minute to form an a thin layer ofconductive polymer (PEDOT) on the dielectric of the anodized anodes. Theanodized anodes were washed to remove excess monomer and by-products ofthe reactions after the completion of 60 minutes of polymerization. Thisprocess was repeated until a sufficient thickness was achieved. Acommercial conductive polymer dispersion Clevios® KV2 was applied andsubsequently dried to form an external polymer layer. This process wasrepeated 4 times. The parts were inspected under microscope for cornersand edge coverage. A sequential coating of a graphite layer and a silverlayer were applied to produce a solid electrolytic capacitor. Parts wereassembled and packaged.

Comparative Example 8

A series of tantalum anodes (33 microfarads, 35V) were prepared. Thetantalum was anodized to form a dielectric on the tantalum anode. Theanodes thus formed was dipped into a solution of iron (III)toluenesulfonate oxidant for 1 minute and sequentially dipped intoethyldioxythiophene monomer for 1 minute to form an a thin layer ofconductive polymer (PEDOT) on the dielectric of the anodized anodes. Theanodized anodes were washed to remove excess monomer and by-products ofthe reactions after the completion of 60 minutes of polymerization. Thisprocess was repeated until a sufficient thickness was achieved.Conductive polymer dispersion from Comparative Example 4 was applied toform an external polymer layer. After drying, alternating layers of acommercial crosslinker solution, Clevios® K Primer, and conductivepolymer dispersion from Comparison Example 2 were applied and repeated 4times. The parts were washed with hot water to remove excess Clevios® KPrimer and subsequently dried in oven. The parts were inspected undermicroscope for corners and edge coverage. A sequential coating of agraphite layer and a silver layer were applied to produce a solidelectrolytic capacitor. Parts were assembled and packaged.

Comparative Example 9

A series of tantalum anodes (33 microfarads, 35V) were prepared. Thetantalum was anodized to form a dielectric on the tantalum anode. Theanodes thus formed were dipped into a solution of iron (III)toluenesulfonate oxidant for 1 minute and sequentially dipped intoethyldioxythiophene monomer for 1 minute to form a thin layer ofconductive polymer (PEDOT) on the dielectric of the anodized anodes. Theanodized anodes were washed to remove excess monomer and by-products ofthe reactions after the completion of 60 minutes of polymerization. Thisprocess was repeated until a sufficient thickness was achieved. Acommercial conductive polymer dispersion Clevios® KV2 was applied toform an external polymer layer. After drying, alternating layers of acommercial crosslinker solution, Clevios® K Primer, and conductivepolymer dispersion from Comparison Example 2 were applied and repeated 4times. The parts were washed with hot water to remove excess Clevios® KPrimer and subsequently dried in an oven. The parts were inspected undermicroscope for corners and edge coverage. A sequential coating of agraphite layer and a silver layer were applied to produce a solidelectrolytic capacitor. Parts were assembled and packaged.

The performance results of inventive conductive polymer dispersion insolid electrolytic capacitor are summarized in Table 1 and Table 2.

TABLE 1 Effect of bimodal particle size distribution on coverage.Coverage Example 7 100% Example 8 100% Comparison Example 5  85%Comparison example 6  90% Comparison example 7  90%

TABLE 2 ESR and Leakage reliability under humid atmosphere Load 85° C./Biased HAST 85% RH Mean leakage failure ESR (mΩ) No. of No. of 1000failed pcs failed pcs 0 Hr ESR Hrs at 0 Hr at 63 Hrs Inventive Example 832.1 37.4 0/20 0/20 Comparison Example 8 27.1 71.1 0/20 3/20 ComparisonExample 9 31.7 1426 0/20 4/20

The advantages of the dispersion with at least a bi-modal sizedistribution are manifest in improvements in the coating quality andperformance of the solid electrolytic capacitor. The invention has beendescribed with reference to the preferred embodiments without limitthereto. One of skill in the art would realize additional embodimentsand improvements which are within the metes and bounds of the inventionas more specifically set forth in the claims appended hereto.

The invention claimed is:
 1. A dispersion comprising: first particlescomprising conductive polymer and polyanion wherein said first particleshave an average particle diameter of at least 1 micron to no more than10 microns; second particles comprising said conductive polymer and saidpolyanion wherein said second particles have an average particlediameter of at least 1 nm to no more than 600 nm; wherein saidconductive polymer comprises conjugated groups having the structure ofFormula I:

wherein: R¹ and R² independently represent linear or branched C₁-C₁₆alkyl or C₂-C₁₈ alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzylwhich are unsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy,halogen or OR³; or R¹ and R², taken together, are linear C₁-C₆ alkylenewhich is unsubstituted or substituted by C₁-C₆ alkyl, C₁-C₆ alkoxy,halogen, C₃-C₈ cycloalkyl, phenyl, benzyl, C₁-C₄ alkylphenyl, C₁-C₄alkoxyphenyl, halophenyl, C₁-C₄ alkylbenzyl, C₁-C₄ alkoxybenzyl orhalobenzyl, 5-, 6-, or 7-membered heterocyclic structure containing twooxygen elements; R³ represents hydrogen, linear or branched C₁-C₁₆ alkylor C₂-C₁₈ alkoxyalkyl; or are C₃-C₈ cycloalkyl, phenyl or benzyl whichare unsubstituted or substituted by C₁-C₆ alkyl; and X is S, N or O; andsaid polyanion is represented by Formula 2:A_(x)B_(y)C_(z)   Formula 2 wherein: A is polystyrenesulfonic acid orsalt of polystyrenesulfonate; B and C separately represent polymerizedunits substituted with a group selected from: -carboxyl groups; —C(O)OR⁶wherein R⁶ is selected from the group consisting of: an alkyl of 1 to 20carbons optionally substituted with a functional group selected from thegroup consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, azide, phosphate, acrylate, anhydride and—(CHR⁷CH₂O)_(b)—R⁸ wherein: R⁷ is selected from a hydrogen or an alkylof 1 to 7 carbons; b is an integer from 1 to the number sufficient toprovide a molecular weight of up to 200,000 for the —CHR⁷CH₂O— group;and R⁸ is selected from the group consisting of hydrogen, silane,phosphate, acrylate, an alkyl of 1 to 9 carbons optionally substitutedwith a functional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate, and anhydride; —C(O)—NHR⁹ wherein: R⁹ ishydrogen or an alkyl of 1 to 20 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride; —C₆H₄—R¹⁰ wherein: R¹⁰ isselected from: a hydrogen or alkyl optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,phosphate, azide, acrylate and anhydride; a reactive group selected fromthe group consisting of hydroxyl, carboxyl, amine, epoxy, silane, imide,amide, thiol, alkene, alkyne, phosphate, azide, acrylate, anhydride and—(O(CHR¹¹CH₂O)_(d)—R¹² wherein: R¹¹ is a hydrogen or an alkyl of 1 to 7carbons; d is an integer from 1 to the number sufficient to provide amolecular weight of up to 200,000 for the —CHR¹¹CH₂O— group; R¹² isselected from the group consisting of hydrogen, an alkyl of 1 to 9carbons optionally substituted with a functional group selected from thegroup consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide,imide, thiol, alkene, alkyne, phosphate, azide, acrylate and anhydride;—C₆H₄—O—R¹³ wherein: R¹³ is selected from: a hydrogen or an alkyloptionally substituted with a reactive group selected from the groupconsisting of hydroxyl, carboxyl, amine, epoxy, silane, amide, imide,thiol, alkene, alkyne, azide, acrylate, phosphate and anhydride; areactive group selected from the group consisting of epoxy, silane,alkene, alkyne, acrylate, phosphate and —(CHR¹⁴CH₂O)_(e)—R¹⁵ wherein:R¹⁴ is a hydrogen or an alkyl of 1 to 7 carbons; e is an integer from 1to the number sufficient to provide a molecular weight of up to 200,000for the —CHR¹⁴CH₂O— group; and R¹⁵ is selected from the group consistingof hydrogen and an alkyl of 1 to 9 carbons optionally substituted with afunctional group selected from the group consisting of hydroxyl,carboxyl, amine, epoxy, silane, amide, imide, thiol, alkene, alkyne,azide, acrylate, phosphate and anhydride; x, y and z, taken together aresufficient to form a polyanion with a molecular weight of at least 100to no more than 500,000; y/x is 0 to 100; and z is 0 to a ratio z/x ofno more than 100 wherein a portion of said dispersion is furthersubjected to rotor-stator high shear mixing, ultrasonic mixing, acousticmixing, high-pressure homogenizing or high shearing homogenizing.
 2. Thedispersion of claim 1 wherein said first particles have a D₅₀ which isat least 1 micron to no more than 5 microns.
 3. The dispersion of claim2 wherein said first particles have a D₅₀ which is at least and evenmore preferably at least 2 microns to no more than 4 microns.
 4. Thedispersion of claim 1 wherein said second particles have a D₅₀ of 100 nmto no more than 500 nm.
 5. The dispersion of claim 4 wherein said secondparticles have a D₅₀ of and even more preferably at least 200 nm to nomore than 400 nm.
 6. The dispersion of claim 1 wherein R¹ and R² ofFormula I are taken together to represent —O—(CHR⁴)_(n)—O— wherein: n isan integer from 1 to 5; R⁴ is independently selected from hydrogen; alinear or branched C₁ to C₁₈ alkyl radical C₅ to C₁₂ cycloalkyl radical,C₆ to C₁₄ aryl radical Cr to C₁₈ aralkyl radical or C₁ to C₄hydroxyalkyl radical, optionally substituted with a functional groupselected from carboxylic acid, hydroxyl, amine, substituted amines,alkene, acrylate, thiol, alkyne, azide, sulfate, sulfonate, sulfonicacid, imide, amide, epoxy, anhydride, silane, and phosphate; hydroxylradical; or R⁴ is selected from —(CHR⁵)_(a)—R¹⁶; —O(CHR⁵)_(a)R¹⁶;—CH₂O(CHR⁵)_(a)R¹⁶; —CH₂O(CH₂CHR⁵O)_(a)R¹⁶, or R⁴ is a functional groupselected from the group consisting of hydroxyl, carboxyl, amine, epoxy,amide, imide, anhydride, hydroxymethyl, alkene, thiol, alkyne, azide,sulfonic acid, benzene sulfonic acidsulfate, SO₃M, anhydride, silane,acrylate and phosphate; R⁵ is H or alkyl chain of 1 to 5 carbonsoptionally substituted with a functional groups selected from carboxylicacid, hydroxyl, amine, alkene, thiol, alkyne, azide, epoxy, acrylate andanhydride; R¹⁶ is H or SO₃M or an alkyl chain of 1 to 5 carbonsoptionally substituted with a functional groups selected from carboxylicacid, hydroxyl, amine, substituted amines, alkene, thiol, alkyne, azide,amide, imide, sulfate, SO₃M, amide, epoxy, anhydride, silane, acrylateand phosphate; a is integer from 0 to 10; and M is a H or cationpreferably selected from ammonia, sodium or potassium.
 7. The dispersionof claim 6 wherein n is
 2. 8. The dispersion of claim 1 wherein saidconductive polymer is water-soluble or water-dispersible.
 9. Thedispersion of claim 1 wherein said conductive polymer is selected fromthe group consisting of poly(3,4-ethylenedioxythiophene),poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxy)-1-butane-sulphonicacid or salt),poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxy)-1-propane-sulphonicacid or salt),poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxy)-1-methyl-1-propane-sulphonicacid or salt), poly(4-(2,3-dihydrothieno-[3,4-b][1,4]dioxin-2-yl)methoxyalcohol, polythiophene, poly(3-methylthiophene), poly(3-hexylthiophene),poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene),poly(3-dodecylthiophene), poly(3-octadecylthiophene),poly(3-bromothiophene), poly(3,4-dimethylthiophene),poly(3,4-dibutylthiophene), poly(3-hydroxythiophene),poly(3-methoxythiophene), poly(3-ethoxythiophene),poly(3-butoxythiophene), poly(3-hexyloxythiophene),poly(3-heptyloxythiophene), poly(3-octyloxythiophene),poly(3-decyloxythiophene), poly(3-dodecyloxythiophene),poly(3-octadecyloxythiophene), poly(3,4-dihydroxythiophene),poly(3,4-dimethoxythiophene), poly(3,4-ethylenedioxythiophene),poly(3,4-propylenedioxythiophene), poly(3,4-butenedioxythiophene),poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene),poly(3-methyl-4-carboxyethylthiophene) andpoly(3-methyl-4-carboxybutylthiophene).
 10. The dispersion of claim 1wherein said conductive polymer and said polyanion are in a molar ratioof 1:0.1 to 0.1:1.
 11. The dispersion of claim 10 wherein saidconductive polymer and said polyanion are in a molar ratio of 1:1 to0.2:1.
 12. The dispersion of claim 11 wherein said conductive polymerand said polyanion are in a molar ratio of 0.8:1 to 0.25:1.
 13. Thedispersion of claim 1 wherein a molar ratio of conductive polymers topolyanion is higher for said first particles than for said secondparticles.